Ah that makes sense and is really unfortunate.
Yeah, it works in godot3 BUT they've not got the .net working yet in Godot 4 sadly. It's on their "to-do" list BUT sadly I didn't realize it. I started trying to get things ported into GD script today to see if I could get a web version up BUT that was going to take an almost complete re-write of my game manger. Live an learn.