From my experience, I can install several repack without any issues on my Mint install (using wine). If you overwhelmed, the easiest way is to add the .exe of your game as non-steam game through the steam and the proton will handle the rest assuming you won’t find dependency issues, if you stumble across problem try to search protondb for solution.
Personally I run my games with wine because I couldn’t figure out how to make use of bottles and lutris (ye I’m weird).
EDIT: Also you can run your modded games on Linux, so far I have tried modded nfs mw (2005) with hard+, underground2, and new vegas, they are works like on Windows.
If shit happen, rtfm. gl op on your journey!
Nice idea but unfortunately good luck convincing everyone to collaborate into single super-game and integrate each “X simulator” as DLC assuming everyone also adhere guideline and consistent