I’m currently using r2modman for Lethal Company modding, but it does lots of other games as well and it’s been working pretty well, so you might want to check that out.

Can I run my whole steam library on linux?

Depends on the games you have. The biggest issue is anti-cheat, so competitive online games have a worse chance of working, nearly all other games should work though.

And also get the same performance from AAA games?

Again depends on the specific games. Some have worse performance than on Windows, some have better performance.

It’s said that less is more but I more or less use less more than more.

Have you tried running your games with gamescope?

Edit: nevermind, I think gamescope doesn’t work with wayland