Well, now I get an ensure about Iris not finding my class, even though I followed the steps described on the linked page in the OP. I submitted a bug report.
I was able to replicate this in a blank project and still get errors, and I’ve been trying a few times already so unless I made typing errors every time, this just isn’t working.
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: === Handled ensure: ===
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error:
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: Ensure condition failed: NetObjectFilterClass != nullptr [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Experimental\Iris\Core\Private\Iris\ReplicationSystem\Filtering\ReplicationFiltering.cpp] [Line: 2455]
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: NetObjectFilter class is not a NetObjectFilter or could not be found: /Script/MyProject.MyDynamicFilter
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: Stack:
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffac4f35858 UnrealEditor-IrisCore.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffac4fbc5b5 UnrealEditor-IrisCore.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffac4fbcdb5 UnrealEditor-IrisCore.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffac4fb2677 UnrealEditor-IrisCore.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffaa34f8d44 UnrealEditor-Engine.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffaa3514e24 UnrealEditor-Engine.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffa688179d8 UnrealEditor-OnlineSubsystemUtils.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffa688196cd UnrealEditor-OnlineSubsystemUtils.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffaa43b3e58 UnrealEditor-Engine.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffaa2cd39ca UnrealEditor-Engine.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffaa2d17218 UnrealEditor-Engine.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffaa078834d UnrealEditor-UnrealEd.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffaa07b3a09 UnrealEditor-UnrealEd.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffaa07891fc UnrealEditor-UnrealEd.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffaa07d3496 UnrealEditor-UnrealEd.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffaa07d760e UnrealEditor-UnrealEd.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffaa07d6c0e UnrealEditor-UnrealEd.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffaa003c4a0 UnrealEditor-UnrealEd.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffaa0cbf6b6 UnrealEditor-UnrealEd.dll!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ff74a708e0b UnrealEditor.exe!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ff74a72e33c UnrealEditor.exe!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ff74a72e42a UnrealEditor.exe!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ff74a7318a4 UnrealEditor.exe!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ff74a7470c4 UnrealEditor.exe!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ff74a74a37a UnrealEditor.exe!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffb1559e8d7 KERNEL32.DLL!UnknownFunction []
[2025.04.19-18.59.26:430][431]LogOutputDevice: Error: [Callstack] 0x00007ffb16db14fc ntdll.dll!UnknownFunction []