

I would like to add:
If your game isn’t on Steam, but is on any other popular (or infamous) launcher, odds are it’s also on Lutris with an install script to get it working. Lutris is on Flathub and is officially maintained by the Lutris team so it is available regardless of your Distro.
Lutris is also a good way to install any F2P games that are not on Steam or that you don’t want to rely on Steam for.
Happy gaming!

A lot of dev companies treat their native Linux versions like an afterthought, if they don’t outright outsource the project to a 3rd party. That’s why the Proton version typically works better if the title isn’t Indie. If an Indie dev makes the port, it’s probably alright.
Admittedly, I think this is one thing about Linux gaming that Proton will make worse, now that devs can just test the game in Proton and not even bother with a native Linux version. I don’t foresee that changing unless Linux somehow becomes the overwhelming majority OS, and while I think it will take a good chunk of market share in the coming years, I don’t foresee it becoming the overwhelming majority for some time.