You may want to look into something like Bazzite or Nobara.
Generally though, most distros will be perfectly fine for gaming -- just note that some distros will need a little bit of extra work done for stuff like nvidia drivers, so if you're new to linux, something like those above, which have that done already, will likely be best. Bazzite in particular should be very low maintenance.
I've been having the same problem! I'm also using Mull with uBlock Origin and Dark Reader installed. Clearing the cache may be unnecessary though – I've only had to force stop it to get it working again. I'm going to try turning off Dark Reader for a while to see if it's been causing this incredibly annoying issue (my eyes will hate me for this though).
You should definitely give it a shot! Due to proton, you should be able to play most, if not all, of the games you play om windows (unless they have obnoxious anticheats). A good resource for checking game compatibility on linux is ProtonDB. In terms of performance, there will almost certainly be a slight impact, but in my experience (with an admitingly far more powerful gpu) it really is minimal. And if it really doesn't work out, you can always go back to windows.
The arch wiki is always a good place to check for these sorts of things, whether or not you use arch btw.