diff --git a/src/WinRT.Runtime/ApiCompatBaseline.txt b/src/WinRT.Runtime/ApiCompatBaseline.txt
index c7584cc04..dcf5bea51 100644
--- a/src/WinRT.Runtime/ApiCompatBaseline.txt
+++ b/src/WinRT.Runtime/ApiCompatBaseline.txt
@@ -21,4 +21,5 @@ CannotRemoveAttribute : Attribute 'WinRT.ObjectReferenceWrapperAttribute' exists
 CannotRemoveAttribute : Attribute 'WinRT.ObjectReferenceWrapperAttribute' exists on 'WinRT.IInspectable' in the contract but not the implementation.
 MembersMustExist : Member 'protected void Microsoft.UI.Xaml.LayoutCycleException..ctor(System.Runtime.Serialization.SerializationInfo, System.Runtime.Serialization.StreamingContext)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'protected void Microsoft.UI.Xaml.Automation.ElementNotAvailableException..ctor(System.Runtime.Serialization.SerializationInfo, System.Runtime.Serialization.StreamingContext)' does not exist in the implementation but it does exist in the contract.
-Total Issues: 122
+CannotChangeAttribute : Attribute 'System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembersAttribute' on 'WinRT.WindowsRuntimeHelperTypeAttribute.HelperType' changed from '[DynamicallyAccessedMembersAttribute(DynamicallyAccessedMemberTypes.PublicFields | DynamicallyAccessedMemberTypes.PublicMethods | DynamicallyAccessedMemberTypes.PublicNestedTypes)]' in the contract to '[DynamicallyAccessedMembersAttribute(DynamicallyAccessedMemberTypes.PublicFields | DynamicallyAccessedMemberTypes.PublicMethods)]' in the implementation.
+Total Issues: 123
diff --git a/src/WinRT.Runtime/AttributeMessages.net5.cs b/src/WinRT.Runtime/AttributeMessages.net5.cs
index 91dc012ae..04eda9fa3 100644
--- a/src/WinRT.Runtime/AttributeMessages.net5.cs
+++ b/src/WinRT.Runtime/AttributeMessages.net5.cs
@@ -10,6 +10,11 @@ internal static class AttributeMessages
         /// </summary>
         public const string GenericDeprecatedMessage = "This method is deprecated and will be removed in a future release.";
 
+        /// <summary>
+        /// Message for a generic annotation for a method using <see cref="System.Diagnostics.CodeAnalysis.RequiresUnreferencedCodeAttribute"/>.
+        /// </summary>
+        public const string GenericRequiresUnreferencedCodeMessage = "This method is not trim-safe, and is only supported for use when not using trimming (or AOT).";
+
         /// <summary>
         /// Message for marshalling or generic code requiring <see cref="System.Diagnostics.CodeAnalysis.RequiresUnreferencedCodeAttribute"/>.
         /// </summary>
diff --git a/src/WinRT.Runtime/Attributes.cs b/src/WinRT.Runtime/Attributes.cs
index 2d332a5cb..be07a166e 100644
--- a/src/WinRT.Runtime/Attributes.cs
+++ b/src/WinRT.Runtime/Attributes.cs
@@ -97,7 +97,7 @@ public WindowsRuntimeHelperTypeAttribute()
 
         public WindowsRuntimeHelperTypeAttribute(
 #if NET
-            [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods | DynamicallyAccessedMemberTypes.PublicNestedTypes | DynamicallyAccessedMemberTypes.PublicFields)]
+            [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods | DynamicallyAccessedMemberTypes.PublicFields)]
 #endif
             Type helperType)
         {
@@ -105,7 +105,7 @@ public WindowsRuntimeHelperTypeAttribute(
         }
 
 #if NET
-        [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods | DynamicallyAccessedMemberTypes.PublicNestedTypes | DynamicallyAccessedMemberTypes.PublicFields)]
+        [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods | DynamicallyAccessedMemberTypes.PublicFields)]
 #endif
         public Type HelperType { get; }
     }
diff --git a/src/WinRT.Runtime/ComWrappersSupport.cs b/src/WinRT.Runtime/ComWrappersSupport.cs
index f805baa28..8bbda9a01 100644
--- a/src/WinRT.Runtime/ComWrappersSupport.cs
+++ b/src/WinRT.Runtime/ComWrappersSupport.cs
@@ -159,7 +159,6 @@ public static void RegisterHelperType(
             Type type,
 #if NET
             [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods |
-                                        DynamicallyAccessedMemberTypes.PublicNestedTypes |
                                         DynamicallyAccessedMemberTypes.PublicFields)]
 #endif
             Type helperType) => TypeExtensions.HelperTypeCache.TryAdd(type, helperType);
diff --git a/src/WinRT.Runtime/Marshalers.cs b/src/WinRT.Runtime/Marshalers.cs
index 88904706e..7ef7247ad 100644
--- a/src/WinRT.Runtime/Marshalers.cs
+++ b/src/WinRT.Runtime/Marshalers.cs
@@ -1375,7 +1375,6 @@ struct MarshalInterface<T>
 #if NET
         [DynamicallyAccessedMembers(
             DynamicallyAccessedMemberTypes.PublicFields |
-            DynamicallyAccessedMemberTypes.PublicNestedTypes |
             DynamicallyAccessedMemberTypes.PublicMethods)]
 #endif
         private static Type _HelperType;
@@ -1383,7 +1382,6 @@ struct MarshalInterface<T>
 #if NET
         [DynamicallyAccessedMembers(
             DynamicallyAccessedMemberTypes.PublicFields |
-            DynamicallyAccessedMemberTypes.PublicNestedTypes |
             DynamicallyAccessedMemberTypes.PublicMethods)]
 #endif
         private static Type HelperType => _HelperType ??= typeof(T).GetHelperType();
diff --git a/src/WinRT.Runtime/MatchingRefApiCompatBaseline.txt b/src/WinRT.Runtime/MatchingRefApiCompatBaseline.txt
index 93601c34a..8079ba1ea 100644
--- a/src/WinRT.Runtime/MatchingRefApiCompatBaseline.txt
+++ b/src/WinRT.Runtime/MatchingRefApiCompatBaseline.txt
@@ -215,4 +215,6 @@ TypesMustExist : Type 'ABI.WinRT.Interop.EventSource<TDelegate>' does not exist
 TypesMustExist : Type 'ABI.WinRT.Interop.EventSourceState<TDelegate>' does not exist in the reference but it does exist in the implementation.
 TypesMustExist : Type 'ABI.WinRT.Interop.EventHandlerEventSource' does not exist in the reference but it does exist in the implementation.
 TypesMustExist : Type 'ABI.WinRT.Interop.EventHandlerEventSource<T>' does not exist in the reference but it does exist in the implementation.
-Total Issues: 217
+CannotChangeAttribute : Attribute 'System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembersAttribute' on 'WinRT.WindowsRuntimeHelperTypeAttribute.HelperType' changed from '[DynamicallyAccessedMembersAttribute(DynamicallyAccessedMemberTypes.PublicFields | DynamicallyAccessedMemberTypes.PublicMethods)]' in the implementation to '[DynamicallyAccessedMembersAttribute(DynamicallyAccessedMemberTypes.PublicFields | DynamicallyAccessedMemberTypes.PublicMethods | DynamicallyAccessedMemberTypes.PublicNestedTypes)]' in the reference.
+CannotRemoveAttribute : Attribute 'System.Diagnostics.CodeAnalysis.UnconditionalSuppressMessageAttribute' exists on 'WinRT.TypeExtensions.FindVftblType(System.Type)' in the implementation but not the reference.
+Total Issues: 219
diff --git a/src/WinRT.Runtime/Projections.cs b/src/WinRT.Runtime/Projections.cs
index 96a68f684..66de64b61 100644
--- a/src/WinRT.Runtime/Projections.cs
+++ b/src/WinRT.Runtime/Projections.cs
@@ -120,7 +120,6 @@ private static void RegisterCustomAbiTypeMapping(
 #if NET
             [DynamicallyAccessedMembers(
                 DynamicallyAccessedMemberTypes.PublicMethods |
-                DynamicallyAccessedMemberTypes.PublicNestedTypes |
                 DynamicallyAccessedMemberTypes.PublicFields)]
 #endif
             Type abiType, 
@@ -143,7 +142,6 @@ private static void RegisterCustomTypeToHelperTypeMapping(
 #if NET
             [DynamicallyAccessedMembers(
                 DynamicallyAccessedMemberTypes.PublicMethods |
-                DynamicallyAccessedMemberTypes.PublicNestedTypes |
                 DynamicallyAccessedMemberTypes.PublicFields)]
 #endif
             Type helperType)
@@ -164,7 +162,6 @@ private static void RegisterCustomTypeToHelperTypeMappingNoLock(
 #if NET
             [DynamicallyAccessedMembers(
                 DynamicallyAccessedMemberTypes.PublicMethods |
-                DynamicallyAccessedMemberTypes.PublicNestedTypes |
                 DynamicallyAccessedMemberTypes.PublicFields)]
 #endif
             Type helperType)
@@ -177,7 +174,6 @@ private static void RegisterCustomAbiTypeMappingNoLock(
 #if NET
             [DynamicallyAccessedMembers(
                 DynamicallyAccessedMemberTypes.PublicMethods |
-                DynamicallyAccessedMemberTypes.PublicNestedTypes |
                 DynamicallyAccessedMemberTypes.PublicFields)]
 #endif
             Type abiType, 
@@ -200,7 +196,6 @@ private static void RegisterCustomAbiTypeMapping(
 #if NET
             [DynamicallyAccessedMembers(
                 DynamicallyAccessedMemberTypes.PublicMethods |
-                DynamicallyAccessedMemberTypes.PublicNestedTypes |
                 DynamicallyAccessedMemberTypes.PublicFields)]
 #endif
             Type abiType)
@@ -221,7 +216,6 @@ private static void RegisterCustomAbiTypeMappingNoLock(
 #if NET
             [DynamicallyAccessedMembers(
                 DynamicallyAccessedMemberTypes.PublicMethods |
-                DynamicallyAccessedMemberTypes.PublicNestedTypes |
                 DynamicallyAccessedMemberTypes.PublicFields)]
 #endif
             Type abiType)
@@ -233,7 +227,6 @@ private static void RegisterCustomAbiTypeMappingNoLock(
 #if NET
         [return: DynamicallyAccessedMembers(
             DynamicallyAccessedMemberTypes.PublicMethods |
-            DynamicallyAccessedMemberTypes.PublicNestedTypes |
             DynamicallyAccessedMemberTypes.PublicFields)]
 #endif
         public static Type FindCustomHelperTypeMapping(Type publicType, bool filterToRuntimeClass = false)
diff --git a/src/WinRT.Runtime/TypeExtensions.cs b/src/WinRT.Runtime/TypeExtensions.cs
index 2cd70aa5f..def3b4f2f 100644
--- a/src/WinRT.Runtime/TypeExtensions.cs
+++ b/src/WinRT.Runtime/TypeExtensions.cs
@@ -21,7 +21,6 @@ static class TypeExtensions
 
 #if NET
         [return: DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods |
-                                            DynamicallyAccessedMemberTypes.PublicNestedTypes | 
                                             DynamicallyAccessedMemberTypes.PublicFields)]
         [SuppressMessage("Trimming", "IL2073", Justification = "Matching trimming annotations are used at all callsites registering helper types present in the cache.")]
 #endif
@@ -29,7 +28,6 @@ public static Type FindHelperType(this Type type)
         {
 #if NET
             [return: DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods |
-                                                DynamicallyAccessedMemberTypes.PublicNestedTypes |
                                                 DynamicallyAccessedMemberTypes.PublicFields)]
 #endif
             static Type FindHelperTypeNoCache(Type type)
@@ -76,7 +74,7 @@ static Type FindHelperTypeNoCache(Type type)
 #if NET
             [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:RequiresUnreferencedCode",
                 Justification = "No members of the generic type are dynamically accessed other than for the attributes on it.")]
-            [return: DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods | DynamicallyAccessedMemberTypes.PublicNestedTypes | DynamicallyAccessedMemberTypes.PublicFields)]
+            [return: DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods | DynamicallyAccessedMemberTypes.PublicFields)]
 #endif
             static Type GetHelperTypeFromAttribute(WindowsRuntimeHelperTypeAttribute helperTypeAtribute, Type type)
             {
@@ -119,8 +117,7 @@ static Type FindHelperTypeFallback(Type type)
         }
 
 #if NET
-        [return: DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods | 
-                                            DynamicallyAccessedMemberTypes.PublicNestedTypes |
+        [return: DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods |
                                             DynamicallyAccessedMemberTypes.PublicFields)]
 #endif
         public static Type GetHelperType(this Type type)
@@ -140,13 +137,10 @@ public static Type GetGuidType(this Type type)
         }
 
 #if NET
-        [return: DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicFields)]
-#endif
-        public static Type FindVftblType(
-#if NET
-            [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicNestedTypes)]
+        [UnconditionalSuppressMessage("AOT", "IL3050", Justification = "The fallback path is not AOT-safe by design (to avoid annotations).")]
+        [UnconditionalSuppressMessage("Trimming", "IL2026", Justification = "The fallback path is not trim-safe by design (to avoid annotations).")]
 #endif
-            this Type helperType)
+        public static Type FindVftblType(this Type helperType)
         {
 #if NET
             if (!RuntimeFeature.IsDynamicCodeCompiled)
@@ -155,23 +149,49 @@ public static Type FindVftblType(
             }
 #endif
 
-            Type vftblType = helperType.GetNestedType("Vftbl");
-            if (vftblType is null)
-            {
-                return null;
-            }
-            if (helperType.IsGenericType && vftblType is object)
+#if NET8_0_OR_GREATER
+            [RequiresDynamicCode(AttributeMessages.MarshallingOrGenericInstantiationsRequiresDynamicCode)]
+#endif
+#if NET
+            [DynamicDependency(DynamicallyAccessedMemberTypes.All, "ABI.Windows.Foundation.IAsyncActionWithProgress`1+Vftbl", "Microsoft.Windows.SDK.NET")]
+            [DynamicDependency(DynamicallyAccessedMemberTypes.All, "ABI.Windows.Foundation.IAsyncOperationWithProgress`2+Vftbl", "Microsoft.Windows.SDK.NET")]
+            [DynamicDependency(DynamicallyAccessedMemberTypes.All, "ABI.Windows.Foundation.IAsyncOperation`1+Vftbl", "Microsoft.Windows.SDK.NET")]
+            [DynamicDependency(DynamicallyAccessedMemberTypes.All, "ABI.Windows.Foundation.Collections.IMapChangedEventArgs`1+Vftbl", "Microsoft.Windows.SDK.NET")]
+            [DynamicDependency(DynamicallyAccessedMemberTypes.All, "ABI.Windows.Foundation.Collections.IObservableMap`2+Vftbl", "Microsoft.Windows.SDK.NET")]
+            [DynamicDependency(DynamicallyAccessedMemberTypes.All, "ABI.Windows.Foundation.Collections.IObservableVector`1+Vftbl", "Microsoft.Windows.SDK.NET")]
+            [DynamicDependency(DynamicallyAccessedMemberTypes.All, "ABI.System.EventHandler`1+Vftbl", "WinRT.Runtime")]
+            [DynamicDependency(DynamicallyAccessedMemberTypes.All, "ABI.System.Collections.Generic.KeyValuePair`2+Vftbl", "WinRT.Runtime")]
+            [DynamicDependency(DynamicallyAccessedMemberTypes.All, "ABI.System.Collections.Generic.IEnumerable`1+Vftbl", "WinRT.Runtime")]
+            [DynamicDependency(DynamicallyAccessedMemberTypes.All, "ABI.System.Collections.Generic.IEnumerator`1+Vftbl", "WinRT.Runtime")]
+            [DynamicDependency(DynamicallyAccessedMemberTypes.All, "ABI.System.Collections.Generic.IList`1+Vftbl", "WinRT.Runtime")]
+            [DynamicDependency(DynamicallyAccessedMemberTypes.All, "ABI.System.Collections.Generic.IReadOnlyList`1+Vftbl", "WinRT.Runtime")]
+            [DynamicDependency(DynamicallyAccessedMemberTypes.All, "ABI.System.Collections.Generic.IDictionary`2+Vftbl", "WinRT.Runtime")]
+            [DynamicDependency(DynamicallyAccessedMemberTypes.All, "ABI.System.Collections.Generic.IReadOnlyDictionary`2+Vftbl", "WinRT.Runtime")]
+            [RequiresUnreferencedCode(AttributeMessages.GenericRequiresUnreferencedCodeMessage)]
+#endif
+            static Type FindVftblTypeFallback(Type helperType)
             {
-#pragma warning disable IL3050 // https://github.com/dotnet/runtime/issues/97273
-                vftblType = vftblType.MakeGenericType(helperType.GetGenericArguments());
-#pragma warning restore IL3050
+                Type vftblType = helperType.GetNestedType("Vftbl");
+                if (vftblType is null)
+                {
+                    return null;
+                }
+                if (helperType.IsGenericType)
+                {
+                    vftblType = vftblType.MakeGenericType(helperType.GetGenericArguments());
+                }
+                return vftblType;
             }
-            return vftblType;
+
+            return FindVftblTypeFallback(helperType);
         }
 
+#if NET
+        [SuppressMessage("Trimming", "IL2075", Justification = "The path using vtable types is a fallback and is not trim-safe by design.")]
+#endif
         internal static IntPtr GetAbiToProjectionVftblPtr(
 #if NET
-            [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicFields | DynamicallyAccessedMemberTypes.PublicNestedTypes)]
+            [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicFields)]
 #endif
             this Type helperType)
         {