Does MouseInjector work on Wayland yet? To test, you'll need:
>An old version of Duckstation
https://github.com/duckstation/old-releases/releases/tag/v0.1-5943
>A compatible game (I choose Mega Man Legends 2)
https://vimm.net/vault/5972
>And MouseInjector itself
https://github.com/garungorp/MouseInjectorDolphinDuck