Linux

The only thing that still makes me keep a Windows partition on my computer is Valorant, I want to start playing CounterStrike so I can drop this damn malware game.

You can just check on protondb if any game you want to play works with Proton or doesn't at all. But generally almost anything that doesn't require an anticheat will work.

I can only speak for Witcher 3 of the games you've listed and it plays really great!

I'd say about 95 percent of my steam collection works with little to no tweaking required these days. Skyrim works, throw any mods you want at it. Witcher 3 runs great. RDR2 and any civ 1-6 all run perfectly. Baulders Gate 3 runs smooth as butter.

There's the odd game here and there that doesn't work well or at all but most things just work. I think the main thing that doesn't work is anticheat enabled online games. I don't play those though so I can't really comment on their state of play outside of that.

I've had varying luck with the standard distros, but when I found Nobara, somehow all my gaming problems went away. And now everything just works, actually better than on Windows. I don't have the time or energy to find out what they're doing better for my particular case, but apparently something.

(avoid KDE)

I couldn't get RDR2 to play, but I'm also a noob. I have a drive with windows just for playin the games I can't run in linux, and maybe I boot it once a month.

Outside the few games like valorant and destiny 2, literally everything else I've tried runs just fine on Linux. Wine/Proton has gotten really good these past 2 years. Even on Wayland, which has historically been bad for gaming things just work nowadays.