If you want to play anything with anticheat, you can’t on a steamdeck. And gamepass was my number one reason to not get a steamdeck. I play Xbox too, I might as well get the most bang for my buck if I already subscribe.
Sea of Thieves has a shit ton of Tumbleweed reviews on protondb. You should read them. There’s also a fair amount of other distros that say they work fine. Now my own anecdotal experience, I couldn’t get anything to work on my arch install. But I was dumb as hell and didn’t want to use a desktop environment on a desktop.