Most games are compatible, you can also check https://protondb.com/ for each game, how people play it and how they run it. It's a very neat website!
About the jump: Do it now, and you'll thank yourself later. I did it with no prior experience myself and didn't find it difficult at all tbh, as previous comment suggested, try Mint first of you're afraid. And if you want an easy to use one that also focus on a bit of gaming then try PopOS! Don't let the amount of choices discourage or confuse you, just pick one and go with it. Feel free to message me if you ever need any help 🌻