This big thing for this update is that I was able to get @Ed Harvey's effect plugins to work! And that's basically it, but that's a really big win
In order to get it working, the DLL is modified to fix up the code that doesn't work on .NET 5. There were two properties of type ContextMenu that had to be removed (they weren't being used), and some reflection against some fields in VisualStyleRenderer that were renamed. This was pretty easy with the use of Mono.Cecil.