I used to game on Linux back in the late 2000s through Wine. And I always found the mouse support to be jarring, even if I could get support to a decent level, for some reason the mouse input was never quite as fluid as it should have been.

And now I'm reluctant to move back to Linux for gaming, even though they've clearly come so far. I guess I should just go ahead and give it another shot.

Stating my bias up front, I've been using Linux since Windows Vista, and I'm a fan. That said, I have experienced the same things you did whenever I needed to run Wine for... well, anything. It was clunky as hell.

You should absolutely revisit. Proton has changed the game. Literally the only game I've tried that was remotely difficult to play in SteamOS is Minecraft, likely because Microsoft owns it now. But I was able to get that working too (if anyone's wondering: you want Minecraft Bedrock Launcher, which is in the Discover store if you're on the Steam Deck and here[1] if you're somewhere else; basically it downloads and runs the Android version of Minecraft through a small translation layer, which is essentially identical to the Windows version).

Speed also is greatly improved from previous solutions. Games played through Proton are often very close in terms of performance to playing them natively.

It has come lightyears.

ProtonDB has a feature where you can give it access to your Steam account for reading and it'll give you a full report based on your personal library: https://www.protondb.com/profile

And I find if anything it tends to the conservative. I've encountered a few things where it was overoptimistic but its outweighed by the stuff that was supported even better than ProtonDB said.

In the late 2000s, I played a few things, but I went in with the assumption it either wouldn't work, or wouldn't work without tweaking. Now I go in with the assumption that it will work unless otherwise indicated. Except multiplayer shooters and VR.