It's worth noting that the native Linux version of games is often buggy and a far worse experience than the Windows version running on Proton. Valve itself is infamous for this: the Left 4 Dead 2 native game has multiple very annoying bugs that have been known for 15 years, and that Valve still hasn't fixed. Unfortunately, there is (another) bug that prevents the Windows version running on Proton from connecting to VAC-secure servers or I would have ditched the Linux version long ago.
At this point game devs should just discontinue the native version if they aren't going to properly support it and just make sure the game runs flawlessly on Proton.
At this point game devs should just discontinue the native version if they aren't going to properly support it and just make sure the game runs flawlessly on Proton.