Decided I would try using Steam on PopOS.. I didn't realize how long it has been since I've apparently played a steam game

Just that basically every game works. The majority will work with no tinkering, and then a small amount will need very basic tinkering (talking like adding three words to your steam launch commands or something).

There is a very small % of games that is "unsupported," and even those you can usually get working. For example, Dark Souls: Prepare to Die Edition is labeled as "unsupported" on Steam, but I got it to work just fine (with DSFix too) with hardly any tinkering. I saw Racettear unplayed and "unsupported" in my library the other night, and it took me about 2 minutes to get it running (at the wrong resolution), and another 5 to get it scaled to the right resolution.

Check protondb.com for some better info on whether or not a game will work (and if any tinkering is needed, what it is). Oh yeah, if you're not aware, "Proton" is the translation layer that makes all of this possible. Steam integrates it automatically, and you just need to select which version you want your game to use from the dropdown in the "compatibility" page in the settings for each game (usually just the most recent version, though there are modified custom versions of proton like GE, that work better for some games). Many games these days will have the option to play the native Linux runtime... It is worth a shot, but I have found that, more often than not, the Windows version played through Proton, plays better. Yes, seriously.

The only games that appear to truly not work on Linux are games with anti-cheat. And even then, it's not all of them, only the ones where the devs decided for some reason not to allow Linux players.