This repo is a minimal example of using IL2CPP from a third-party DLL loaded into the target game, it was done a long time ago i'm only uploading it now.
The actual features were never finished. It was thrown together quickly to clear the game for fun and see the rest of the content.
There are issues that come from the game itself, and a lot is missing from the IL2CPP side. It is pretty bare bones, but you never know - somebody might find a use for it.