Fix Steam Deck (or other handhelds with SteamOS) Controls!

All you need to do to make it work is switch to Proton version 9.0-4. To do so, follow the instructions at this link. For SteamOS, you can do this all in Gaming Mode.

Guide from Gaming on Linux[www.gamingonlinux.com]

After this, you should be good to go. Your Steam Deck or other gaming handheld may need to download this version of Proton before launching the game again, but the controls should work now!