Steam has some good options. And, if you can play it on the Steamdeck, it will probably work on a Linux desktop.

But, if you have specific gaming needs, please check those first. Some games just don’t work, and I wouldn’t want your to trade OSes (which all have their own frustrations) and then find yourself unable to game.

Preferably find someone local that already uses Linux and is willing to help you out some. LUGs (Linux User Groups) used to be a thing; maybe there’s one near you. A lot of Linux users like gaming these days, though plenty of them still dual-boot.