diff --git a/Content.IntegrationTests/Tests/Atmos/AlarmThresholdTest.cs b/Content.IntegrationTests/Tests/Atmos/AlarmThresholdTest.cs
index 654a842084..9ebc319d43 100644
--- a/Content.IntegrationTests/Tests/Atmos/AlarmThresholdTest.cs
+++ b/Content.IntegrationTests/Tests/Atmos/AlarmThresholdTest.cs
@@ -30,10 +30,8 @@ namespace Content.IntegrationTests.Tests.Atmos
             var prototypeManager = server.ResolveDependency<IPrototypeManager>();
             AtmosAlarmThreshold threshold = default!;
 
-            await server.WaitPost(() =>
-            {
-                threshold = prototypeManager.Index<AtmosAlarmThreshold>("AlarmThresholdTestDummy");
-            });
+            var proto = prototypeManager.Index<AtmosAlarmThresholdPrototype>("AlarmThresholdTestDummy");
+            threshold = new(proto);
 
             await server.WaitAssertion(() =>
             {
diff --git a/Content.IntegrationTests/Tests/PrototypeSaveTest.cs b/Content.IntegrationTests/Tests/PrototypeSaveTest.cs
index 1213d652e0..74123b5bc7 100644
--- a/Content.IntegrationTests/Tests/PrototypeSaveTest.cs
+++ b/Content.IntegrationTests/Tests/PrototypeSaveTest.cs
@@ -232,7 +232,7 @@ public sealed class PrototypeSaveTest
             SerializationHookContext hookCtx,
             ISerializationContext? context, ISerializationManager.InstantiationDelegate<EntityUid>? instanceProvider)
         {
-            return EntityUid.Invalid;
+            return EntityUid.Parse(node.Value);
         }
     }
 }
diff --git a/Content.IntegrationTests/Tests/PrototypeTests/PrototypeTests.cs b/Content.IntegrationTests/Tests/PrototypeTests/PrototypeTests.cs
index 77f60800fc..8b7c73380e 100644
--- a/Content.IntegrationTests/Tests/PrototypeTests/PrototypeTests.cs
+++ b/Content.IntegrationTests/Tests/PrototypeTests/PrototypeTests.cs
@@ -1,5 +1,8 @@
+#nullable enable
 using System.Collections.Generic;
 using Robust.Shared.Prototypes;
+using Robust.Shared.Serialization.Manager;
+using Robust.Shared.Serialization.Markdown;
 using Robust.Shared.Serialization.Markdown.Validation;
 using Robust.UnitTesting;
 
@@ -59,4 +62,126 @@ public sealed class PrototypeTests
             }
         });
     }
+
+    /// <summary>
+    /// This test writes all known prototypes as yaml files, reads them again, then serializes them again.
+    /// </summary>
+    [Test]
+    public async Task ServerPrototypeSaveLoadSaveTest()
+    {
+        await using var pairTracker = await PoolManager.GetServerClient();
+        var context = new PrototypeSaveTest.TestEntityUidContext();
+        await SaveLoadSavePrototype(pairTracker.Pair.Server, context);
+        await pairTracker.CleanReturnAsync();
+    }
+
+    /// <summary>
+    /// This test writes all known prototypes as yaml files, reads them again, then serializes them again.
+    /// </summary>
+    [Test]
+    public async Task ClientPrototypeSaveLoadSaveTest()
+    {
+        await using var pairTracker = await PoolManager.GetServerClient();
+        var context = new PrototypeSaveTest.TestEntityUidContext();
+        await SaveLoadSavePrototype(pairTracker.Pair.Client, context);
+        await pairTracker.CleanReturnAsync();
+    }
+
+    private async Task SaveLoadSavePrototype(
+        RobustIntegrationTest.IntegrationInstance instance,
+        PrototypeSaveTest.TestEntityUidContext ctx)
+    {
+        var protoMan = instance.ResolveDependency<IPrototypeManager>();
+        var seriMan = instance.ResolveDependency<ISerializationManager>();
+        await instance.WaitAssertion(() =>
+        {
+            Assert.Multiple(() =>
+            {
+                foreach (var kind in protoMan.EnumeratePrototypeKinds())
+                {
+                    foreach (var proto in protoMan.EnumeratePrototypes(kind))
+                    {
+                        var noException = TrySaveLoadSavePrototype(
+                            seriMan,
+                            protoMan,
+                            kind,
+                            proto,
+                            ctx);
+
+                        // This will probably throw an exception for each prototype of this kind.
+                        // We want to avoid having tests crash because they run out of time.
+                        if (!noException)
+                            break;
+                    }
+                }
+            });
+        });
+    }
+
+    /// <returns>False if an exception was caught</returns>
+    private bool TrySaveLoadSavePrototype(
+        ISerializationManager seriMan,
+        IPrototypeManager protoMan,
+        Type kind,
+        IPrototype proto,
+        PrototypeSaveTest.TestEntityUidContext ctx)
+    {
+        DataNode first;
+        DataNode second;
+
+        try
+        {
+            first = seriMan.WriteValue(kind, proto, alwaysWrite: true, context:ctx);
+        }
+        catch (Exception e)
+        {
+            protoMan.TryGetMapping(kind, proto.ID, out var mapping);
+            Assert.Fail($"Caught exception while writing {kind.Name} prototype {proto.ID}. Exception:\n{e}");
+            return false;
+        }
+
+        object? obj;
+        try
+        {
+            obj = seriMan.Read(kind, first, context:ctx);
+        }
+        catch (Exception e)
+        {
+            protoMan.TryGetMapping(kind, proto.ID, out var mapping);
+            Assert.Fail($"Caught exception while re-reading {kind.Name} prototype {proto.ID}." +
+                        $"\nException:\n{e}" +
+                        $"\n\nOriginal yaml:\n{mapping}" +
+                        $"\n\nWritten yaml:\n{first}");
+            return false;
+        }
+
+        Assert.That(obj?.GetType(), Is.EqualTo(proto.GetType()));
+        var deserialized = (IPrototype) obj!;
+
+        try
+        {
+            second = seriMan.WriteValue(kind, deserialized, alwaysWrite: true, context:ctx);
+        }
+        catch (Exception e)
+        {
+            protoMan.TryGetMapping(kind, proto.ID, out var mapping);
+            Assert.Fail($"Caught exception while re-writing {kind.Name} prototype {proto.ID}." +
+                        $"\nException:\n{e}" +
+                        $"\n\nOriginal yaml:\n{mapping}" +
+                        $"\n\nWritten yaml:\n{first}");
+            return false;
+        }
+
+        var diff = first.Except(second);
+        if (diff == null || diff.IsEmpty)
+            return true;
+
+        protoMan.TryGetMapping(kind, proto.ID, out var orig);
+        Assert.Fail($"Re-written {kind.Name} prototype {proto.ID} differs." +
+                    $"\nYaml diff:\n{diff}" +
+                    $"\n\nOriginal yaml:\n{orig}" +
+                    $"\n\nWritten yaml:\n{first}" +
+                    $"\n\nRe-written Yaml:\n{second}");
+        return true;
+    }
 }
diff --git a/Content.Server/Atmos/Monitor/Components/AtmosMonitorComponent.cs b/Content.Server/Atmos/Monitor/Components/AtmosMonitorComponent.cs
index a229544d03..d5055e19e8 100644
--- a/Content.Server/Atmos/Monitor/Components/AtmosMonitorComponent.cs
+++ b/Content.Server/Atmos/Monitor/Components/AtmosMonitorComponent.cs
@@ -1,7 +1,7 @@
 using Content.Shared.Atmos;
 using Content.Shared.Atmos.Monitor;
-using Robust.Shared.Audio;
 using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom.Prototype;
+using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom.Prototype.Dictionary;
 
 namespace Content.Server.Atmos.Monitor.Components;
 
@@ -19,19 +19,19 @@ public sealed class AtmosMonitorComponent : Component
     // Note that this cancels every single network
     // event, including ones that may not be
     // related to atmos monitor events.
-    [ViewVariables]
+    [DataField("netEnabled")]
     public bool NetEnabled = true;
 
-    [DataField("temperatureThreshold", customTypeSerializer: (typeof(PrototypeIdSerializer<AtmosAlarmThreshold>)))]
+    [DataField("temperatureThresholdId", customTypeSerializer: (typeof(PrototypeIdSerializer<AtmosAlarmThresholdPrototype>)))]
     public readonly string? TemperatureThresholdId;
 
-    [ViewVariables]
+    [DataField("temperatureThreshold")]
     public AtmosAlarmThreshold? TemperatureThreshold;
 
-    [DataField("pressureThreshold", customTypeSerializer: (typeof(PrototypeIdSerializer<AtmosAlarmThreshold>)))]
+    [DataField("pressureThresholdId", customTypeSerializer: (typeof(PrototypeIdSerializer<AtmosAlarmThresholdPrototype>)))]
     public readonly string? PressureThresholdId;
 
-    [ViewVariables]
+    [DataField("pressureThreshold")]
     public AtmosAlarmThreshold? PressureThreshold;
 
     // monitor fire - much different from temperature
@@ -41,14 +41,11 @@ public sealed class AtmosMonitorComponent : Component
     [DataField("monitorFire")]
     public bool MonitorFire = false;
 
-    // really messy but this is parsed at runtime after
-    // prototypes are initialized, there's no
-    // way without implementing a new
-    // type serializer
-    [DataField("gasThresholds")]
-    public Dictionary<Gas, string>? GasThresholdIds;
+    [DataField("gasThresholdPrototypes",
+        customTypeSerializer:typeof(PrototypeIdValueDictionarySerializer<Gas, AtmosAlarmThresholdPrototype>))]
+    public Dictionary<Gas, string>? GasThresholdPrototypes;
 
-    [ViewVariables]
+    [DataField("gasThresholds")]
     public Dictionary<Gas, AtmosAlarmThreshold>? GasThresholds;
 
     // Stores a reference to the gas on the tile this is on.
@@ -56,14 +53,16 @@ public sealed class AtmosMonitorComponent : Component
     public GasMixture? TileGas;
 
     // Stores the last alarm state of this alarm.
-    [ViewVariables]
+    [DataField("lastAlarmState")]
     public AtmosAlarmType LastAlarmState = AtmosAlarmType.Normal;
 
-    [ViewVariables] public HashSet<AtmosMonitorThresholdType> TrippedThresholds = new();
+    [DataField("trippedThresholds")]
+    public HashSet<AtmosMonitorThresholdType> TrippedThresholds = new();
 
     /// <summary>
     ///     Registered devices in this atmos monitor. Alerts will be sent directly
     ///     to these devices.
     /// </summary>
-    [ViewVariables] public HashSet<string> RegisteredDevices = new();
+    [DataField("registeredDevices")]
+    public HashSet<string> RegisteredDevices = new();
 }
diff --git a/Content.Server/Atmos/Monitor/Systems/AtmosMonitoringSystem.cs b/Content.Server/Atmos/Monitor/Systems/AtmosMonitoringSystem.cs
index 528c7289da..c7995f4ae6 100644
--- a/Content.Server/Atmos/Monitor/Systems/AtmosMonitoringSystem.cs
+++ b/Content.Server/Atmos/Monitor/Systems/AtmosMonitoringSystem.cs
@@ -37,8 +37,8 @@ public sealed class AtmosMonitorSystem : EntitySystem
 
     public override void Initialize()
     {
-        SubscribeLocalEvent<AtmosMonitorComponent, ComponentInit>(OnAtmosMonitorInit);
         SubscribeLocalEvent<AtmosMonitorComponent, ComponentStartup>(OnAtmosMonitorStartup);
+        SubscribeLocalEvent<AtmosMonitorComponent, MapInitEvent>(OnMapInit);
         SubscribeLocalEvent<AtmosMonitorComponent, AtmosDeviceUpdateEvent>(OnAtmosUpdate);
         SubscribeLocalEvent<AtmosMonitorComponent, TileFireEvent>(OnFireEvent);
         SubscribeLocalEvent<AtmosMonitorComponent, PowerChangedEvent>(OnPowerChangedEvent);
@@ -57,23 +57,28 @@ public sealed class AtmosMonitorSystem : EntitySystem
     {
         atmosMonitor.TileGas = _atmosphereSystem.GetContainingMixture(uid, true);
     }
-
-    private void OnAtmosMonitorInit(EntityUid uid, AtmosMonitorComponent component, ComponentInit args)
+    private void OnMapInit(EntityUid uid, AtmosMonitorComponent component, MapInitEvent args)
     {
         if (component.TemperatureThresholdId != null)
-            component.TemperatureThreshold = new(_prototypeManager.Index<AtmosAlarmThreshold>(component.TemperatureThresholdId));
+        {
+            var proto = _prototypeManager.Index<AtmosAlarmThresholdPrototype>(component.TemperatureThresholdId);
+            component.TemperatureThreshold ??= new(proto);
+        }
 
         if (component.PressureThresholdId != null)
-            component.PressureThreshold = new(_prototypeManager.Index<AtmosAlarmThreshold>(component.PressureThresholdId));
-
-        if (component.GasThresholdIds != null)
         {
-            component.GasThresholds = new();
-            foreach (var (gas, id) in component.GasThresholdIds)
-            {
-                if (_prototypeManager.TryIndex<AtmosAlarmThreshold>(id, out var gasThreshold))
-                    component.GasThresholds.Add(gas, new(gasThreshold));
-            }
+            var proto = _prototypeManager.Index<AtmosAlarmThresholdPrototype>(component.PressureThresholdId);
+            component.PressureThreshold ??= new(proto);
+        }
+
+        if (component.GasThresholdPrototypes == null)
+            return;
+
+        component.GasThresholds ??= new();
+        foreach (var (gas, id) in component.GasThresholdPrototypes)
+        {
+            var proto = _prototypeManager.Index<AtmosAlarmThresholdPrototype>(id);
+            component.GasThresholds.TryAdd(gas, new(proto));
         }
     }
 
diff --git a/Content.Server/DeviceLinking/Components/AutoLinkReceiverComponent.cs b/Content.Server/DeviceLinking/Components/AutoLinkReceiverComponent.cs
index 9a98f81e31..6bf8c7fec5 100644
--- a/Content.Server/DeviceLinking/Components/AutoLinkReceiverComponent.cs
+++ b/Content.Server/DeviceLinking/Components/AutoLinkReceiverComponent.cs
@@ -6,7 +6,7 @@ namespace Content.Server.DeviceLinking.Components;
 [RegisterComponent]
 public sealed class AutoLinkReceiverComponent : Component
 {
-    [DataField("channel", required: true, readOnly: true)]
+    [DataField("channel", required: true)]
     public string AutoLinkChannel = default!;
 }
 
diff --git a/Content.Server/DeviceLinking/Components/AutoLinkTransmitterComponent.cs b/Content.Server/DeviceLinking/Components/AutoLinkTransmitterComponent.cs
index b013d9f578..f42628dff6 100644
--- a/Content.Server/DeviceLinking/Components/AutoLinkTransmitterComponent.cs
+++ b/Content.Server/DeviceLinking/Components/AutoLinkTransmitterComponent.cs
@@ -6,7 +6,7 @@ namespace Content.Server.DeviceLinking.Components;
 [RegisterComponent]
 public sealed class AutoLinkTransmitterComponent : Component
 {
-    [DataField("channel", required: true, readOnly: true)]
+    [DataField("channel", required: true)]
     public string AutoLinkChannel = default!;
 }
 
diff --git a/Content.Server/UserInterface/ActivatableUIComponent.cs b/Content.Server/UserInterface/ActivatableUIComponent.cs
index 5116331456..f1dcb80382 100644
--- a/Content.Server/UserInterface/ActivatableUIComponent.cs
+++ b/Content.Server/UserInterface/ActivatableUIComponent.cs
@@ -25,7 +25,7 @@ namespace Content.Server.UserInterface
         [DataField("adminOnly")]
         public bool AdminOnly { get; set; } = false;
 
-        [DataField("key", readOnly: true, required: true)]
+        [DataField("key", required: true)]
         private string _keyRaw = default!;
 
         [DataField("verbText")]
diff --git a/Content.Server/UserInterface/IntrinsicUIComponent.cs b/Content.Server/UserInterface/IntrinsicUIComponent.cs
index ce344b9686..dd6fcdbd90 100644
--- a/Content.Server/UserInterface/IntrinsicUIComponent.cs
+++ b/Content.Server/UserInterface/IntrinsicUIComponent.cs
@@ -27,12 +27,12 @@ public sealed class IntrinsicUIComponent : Component, ISerializationHooks
 [DataDefinition]
 public struct IntrinsicUIEntry
 {
-    [ViewVariables] public Enum? Key { get; set; } = null;
+    [ViewVariables] public Enum? Key { get; private set; } = null;
 
     /// <summary>
     /// The BUI key that this intrinsic UI should open.
     /// </summary>
-    [DataField("key", readOnly: true, required: true)]
+    [DataField("key", required: true)]
     private string _keyRaw = default!;
 
     /// <summary>
diff --git a/Content.Server/UserInterface/OpenUiActionEvent.cs b/Content.Server/UserInterface/OpenUiActionEvent.cs
index a6942f0e08..59bb4ac9d1 100644
--- a/Content.Server/UserInterface/OpenUiActionEvent.cs
+++ b/Content.Server/UserInterface/OpenUiActionEvent.cs
@@ -7,9 +7,9 @@ namespace Content.Server.UserInterface;
 public sealed class OpenUiActionEvent : InstantActionEvent, ISerializationHooks
 {
     [ViewVariables]
-    public Enum? Key { get; set; }
+    public Enum? Key { get; private set; }
 
-    [DataField("key", readOnly: true, required: true)]
+    [DataField("key", required: true)]
     private string _keyRaw = default!;
 
     void ISerializationHooks.AfterDeserialization()
diff --git a/Content.Shared/Atmos/Monitor/AtmosAlarmThreshold.cs b/Content.Shared/Atmos/Monitor/AtmosAlarmThreshold.cs
index af4f9b850e..1a9fb71a05 100644
--- a/Content.Shared/Atmos/Monitor/AtmosAlarmThreshold.cs
+++ b/Content.Shared/Atmos/Monitor/AtmosAlarmThreshold.cs
@@ -3,77 +3,91 @@ using Robust.Shared.Serialization;
 
 namespace Content.Shared.Atmos.Monitor;
 
-// mostly based around floats and percentages, no literals
-// except for the range boundaries
+
 [Prototype("alarmThreshold")]
-[Serializable, NetSerializable]
-public sealed class AtmosAlarmThreshold : IPrototype, ISerializationHooks
+public sealed class AtmosAlarmThresholdPrototype : IPrototype
 {
     [IdDataField]
     public string ID { get; } = default!;
+
+    [DataField("ignore")]
+    public readonly bool Ignore;
+
+    [DataField("upperBound")]
+    public readonly AlarmThresholdSetting UpperBound = AlarmThresholdSetting.Disabled;
+
+    [DataField("lowerBound")]
+    public readonly AlarmThresholdSetting LowerBound = AlarmThresholdSetting.Disabled;
+
+    [DataField("upperWarnAround")]
+    public readonly AlarmThresholdSetting UpperWarningPercentage = AlarmThresholdSetting.Disabled;
+
+    [DataField("lowerWarnAround")]
+    public readonly AlarmThresholdSetting LowerWarningPercentage = AlarmThresholdSetting.Disabled;
+}
+
+[Serializable, NetSerializable, DataDefinition]
+public sealed class AtmosAlarmThreshold
+{
     [DataField("ignore")]
     public bool Ignore;
 
     [DataField("upperBound")]
-    private AlarmThresholdSetting _UpperBound;
+    private AlarmThresholdSetting _upperBound = AlarmThresholdSetting.Disabled;
 
-    public AlarmThresholdSetting UpperBound { get { return _UpperBound; } private set
+    [DataField("lowerBound")]
+    private AlarmThresholdSetting _lowerBound = AlarmThresholdSetting.Disabled;
+
+    [DataField("upperWarnAround")]
+    public AlarmThresholdSetting UpperWarningPercentage = AlarmThresholdSetting.Disabled;
+
+    [DataField("lowerWarnAround")]
+    public AlarmThresholdSetting LowerWarningPercentage = AlarmThresholdSetting.Disabled;
+
+    public AlarmThresholdSetting UpperBound
+    {
+        get => _upperBound;
+        set
         {
             // Because the warnings are stored as percentages of the bounds,
             // Make a copy of the calculated bounds, so that the real warning amount
             // doesn't change value when user changes the bounds
             var oldWarning = UpperWarningBound;
-            _UpperBound = value;
+            _upperBound = value;
             UpperWarningBound = oldWarning;
         }
     }
 
-    [DataField("lowerBound")]
-    public AlarmThresholdSetting _LowerBound;
-
-    public AlarmThresholdSetting LowerBound { get { return _LowerBound; } private set
+    public AlarmThresholdSetting LowerBound
+    {
+        get => _lowerBound;
+        set
         {
             // Because the warnings are stored as percentages of the bounds,
             // Make a copy of the calculated bounds, so that the real warning amount
             // doesn't change value when user changes the bounds
             var oldWarning = LowerWarningBound;
-            _LowerBound = value;
+            _lowerBound = value;
             LowerWarningBound = oldWarning;
         }
     }
 
-    // upper warning percentage
-    // must always cause UpperWarningBound
-    // to be smaller
-    [DataField("upperWarnAround")]
-    public AlarmThresholdSetting UpperWarningPercentage { get; private set; }
-
-    // lower warning percentage
-    // must always cause LowerWarningBound
-    // to be larger
-    [DataField("lowerWarnAround")]
-    public AlarmThresholdSetting LowerWarningPercentage { get; private set; }
-
     [ViewVariables]
     public AlarmThresholdSetting UpperWarningBound
     {
-        get { return CalculateWarningBound(AtmosMonitorThresholdBound.Upper); }
-        set { UpperWarningPercentage = CalculateWarningPercentage(AtmosMonitorThresholdBound.Upper, value); }
+        get => CalculateWarningBound(AtmosMonitorThresholdBound.Upper);
+        set => UpperWarningPercentage = CalculateWarningPercentage(AtmosMonitorThresholdBound.Upper, value);
     }
 
     [ViewVariables]
     public AlarmThresholdSetting LowerWarningBound
     {
-        get { return CalculateWarningBound(AtmosMonitorThresholdBound.Lower); }
-        set { LowerWarningPercentage = CalculateWarningPercentage(AtmosMonitorThresholdBound.Lower, value); }
+        get => CalculateWarningBound(AtmosMonitorThresholdBound.Lower);
+        set => LowerWarningPercentage = CalculateWarningPercentage(AtmosMonitorThresholdBound.Lower, value);
     }
 
     public AtmosAlarmThreshold()
     {
-        UpperBound = new AlarmThresholdSetting();
-        LowerBound = new AlarmThresholdSetting();
-        UpperWarningPercentage = new AlarmThresholdSetting();
-        LowerWarningPercentage = new AlarmThresholdSetting();
     }
 
     public AtmosAlarmThreshold(AtmosAlarmThreshold other)
@@ -85,12 +99,13 @@ public sealed class AtmosAlarmThreshold : IPrototype, ISerializationHooks
         LowerWarningPercentage = other.LowerWarningPercentage;
     }
 
-    void ISerializationHooks.AfterDeserialization()
+    public AtmosAlarmThreshold(AtmosAlarmThresholdPrototype proto)
     {
-        UpperBound = new AlarmThresholdSetting{ Enabled = UpperBound.Value != 0, Value = UpperBound.Value };
-        LowerBound = new AlarmThresholdSetting{ Enabled = LowerBound.Value != 0, Value = LowerBound.Value };
-        UpperWarningPercentage = new AlarmThresholdSetting{ Enabled = UpperWarningPercentage.Value != 0, Value = UpperWarningPercentage.Value };
-        LowerWarningPercentage = new AlarmThresholdSetting{ Enabled = LowerWarningPercentage.Value != 0, Value = LowerWarningPercentage.Value };
+        Ignore = proto.Ignore;
+        UpperBound = proto.UpperBound;
+        LowerBound = proto.LowerBound;
+        UpperWarningPercentage = proto.UpperWarningPercentage;
+        LowerWarningPercentage = proto.LowerWarningPercentage;
     }
 
     // utility function to check a threshold against some calculated value
@@ -238,38 +253,41 @@ public sealed class AtmosAlarmThreshold : IPrototype, ISerializationHooks
                 break;
         }
     }
+}
 
-    [DataDefinition, Serializable]
-    public struct AlarmThresholdSetting
+[DataDefinition, Serializable]
+public readonly struct AlarmThresholdSetting
+{
+    [DataField("enabled")]
+    public bool Enabled { get; init; } = true;
+
+    [DataField("threshold")]
+    public float Value { get; init; } = 1;
+
+    public static AlarmThresholdSetting Disabled = new() {Enabled = false, Value = 0};
+
+    public AlarmThresholdSetting()
     {
-        [DataField("enabled")]
-        public bool Enabled { get; set; } = false;
-        [DataField("threshold")]
-        public float Value { get; set; } = 0;
+    }
 
-        public AlarmThresholdSetting()
-        {
-        }
+    public static bool operator <=(float a, AlarmThresholdSetting b)
+    {
+        return b.Enabled && a <= b.Value;
+    }
 
-        public static bool operator <=(float a, AlarmThresholdSetting b)
-        {
-            return b.Enabled && a <= b.Value;
-        }
+    public static bool operator >=(float a, AlarmThresholdSetting b)
+    {
+        return b.Enabled && a >= b.Value;
+    }
 
-        public static bool operator >=(float a, AlarmThresholdSetting b)
-        {
-            return b.Enabled && a >= b.Value;
-        }
+    public AlarmThresholdSetting WithThreshold(float threshold)
+    {
+        return this with {Value = threshold};
+    }
 
-        public AlarmThresholdSetting WithThreshold(float threshold)
-        {
-            return new AlarmThresholdSetting{ Enabled = Enabled, Value = threshold };
-        }
-
-        public AlarmThresholdSetting WithEnabled(bool enabled)
-        {
-            return new AlarmThresholdSetting{ Enabled = enabled, Value = Value };
-        }
+    public AlarmThresholdSetting WithEnabled(bool enabled)
+    {
+        return this with {Enabled = enabled};
     }
 }
 
diff --git a/Content.Shared/CartridgeLoader/CartridgeLoaderComponent.cs b/Content.Shared/CartridgeLoader/CartridgeLoaderComponent.cs
index 0fa946b248..2822c76b28 100644
--- a/Content.Shared/CartridgeLoader/CartridgeLoaderComponent.cs
+++ b/Content.Shared/CartridgeLoader/CartridgeLoaderComponent.cs
@@ -42,6 +42,6 @@ public sealed class CartridgeLoaderComponent : Component
     [DataField("diskSpace")]
     public int DiskSpace = 5;
 
-    [DataField("uiKey", readOnly: true, required: true, customTypeSerializer: typeof(EnumSerializer))]
+    [DataField("uiKey", required: true, customTypeSerializer: typeof(EnumSerializer))]
     public Enum UiKey = default!;
 }
diff --git a/Content.Shared/Damage/DamageSpecifierDictionarySerializer.cs b/Content.Shared/Damage/DamageSpecifierDictionarySerializer.cs
index e6ef48bdb0..92f56571a6 100644
--- a/Content.Shared/Damage/DamageSpecifierDictionarySerializer.cs
+++ b/Content.Shared/Damage/DamageSpecifierDictionarySerializer.cs
@@ -39,12 +39,12 @@ public sealed class DamageSpecifierDictionarySerializer : ITypeReader<Dictionary
     {
         var dict = instanceProvider != null ? instanceProvider() : new();
         // Add all the damage types by just copying the type dictionary (if it is not null).
-        if (node.TryGet("types", out var typesNode))
+        if (node.TryGet<MappingDataNode>("types", out var typesNode))
         {
             serializationManager.Read(typesNode, instanceProvider: () => dict, notNullableOverride: true);
         }
 
-        if (!node.TryGet("groups", out var groupsNode))
+        if (!node.TryGet<MappingDataNode>("groups", out var groupsNode))
             return dict;
 
         // Then resolve damage groups and add them
diff --git a/Content.Shared/FixedPoint/FixedPoint2.cs b/Content.Shared/FixedPoint/FixedPoint2.cs
index 2bce52e6cb..e296c276f7 100644
--- a/Content.Shared/FixedPoint/FixedPoint2.cs
+++ b/Content.Shared/FixedPoint/FixedPoint2.cs
@@ -248,7 +248,12 @@ namespace Content.Shared.FixedPoint
 
         public void Deserialize(string value)
         {
-            Value = FromFloat(FloatFromString(value));
+            // TODO implement "lossless" serializer.
+            // I.e., dont use floats.
+            if (value == "MaxValue")
+                Value = int.MaxValue;
+            else
+                Value = FromFloat(FloatFromString(value));
         }
 
         public override readonly string ToString() => $"{ShiftDown().ToString(CultureInfo.InvariantCulture)}";
@@ -260,6 +265,11 @@ namespace Content.Shared.FixedPoint
 
         public readonly string Serialize()
         {
+            // TODO implement "lossless" serializer.
+            // I.e., dont use floats.
+            if (Value == int.MaxValue)
+                return "MaxValue";
+
             return ToString();
         }
 
diff --git a/Resources/Prototypes/Entities/Structures/Piping/Atmospherics/unary.yml b/Resources/Prototypes/Entities/Structures/Piping/Atmospherics/unary.yml
index 7e6f033547..4745a5c7eb 100644
--- a/Resources/Prototypes/Entities/Structures/Piping/Atmospherics/unary.yml
+++ b/Resources/Prototypes/Entities/Structures/Piping/Atmospherics/unary.yml
@@ -38,9 +38,9 @@
     - type: DeviceNetworkRequiresPower
     - type: AtmosDevice
     - type: AtmosMonitor
-      temperatureThreshold: stationTemperature
-      pressureThreshold: stationPressure
-      gasThresholds:
+      temperatureThresholdId: stationTemperature
+      pressureThresholdId: stationPressure
+      gasThresholdPrototypes:
         Oxygen: stationOxygen
         Nitrogen: ignore
         CarbonDioxide: stationCO2
@@ -127,9 +127,9 @@
       examinableAddress: true
     - type: DeviceNetworkRequiresPower
     - type: AtmosMonitor
-      temperatureThreshold: stationTemperature
-      pressureThreshold: stationPressure
-      gasThresholds:
+      temperatureThresholdId: stationTemperature
+      pressureThresholdId: stationPressure
+      gasThresholdPrototypes:
         Oxygen: stationOxygen
         Nitrogen: ignore
         CarbonDioxide: stationCO2
diff --git a/Resources/Prototypes/Entities/Structures/Specific/Atmospherics/sensor.yml b/Resources/Prototypes/Entities/Structures/Specific/Atmospherics/sensor.yml
index 727e88d70f..6fa085646a 100644
--- a/Resources/Prototypes/Entities/Structures/Specific/Atmospherics/sensor.yml
+++ b/Resources/Prototypes/Entities/Structures/Specific/Atmospherics/sensor.yml
@@ -46,9 +46,9 @@
     - type: DeviceNetworkRequiresPower
     - type: AtmosDevice
     - type: AtmosMonitor
-      temperatureThreshold: stationTemperature
-      pressureThreshold: stationPressure
-      gasThresholds:
+      temperatureThresholdId: stationTemperature
+      pressureThresholdId: stationPressure
+      gasThresholdPrototypes:
         Oxygen: stationOxygen
         Nitrogen: ignore
         CarbonDioxide: stationCO2