It’s worth noting that the top 100 games do contain a lot of popular multiplayer games, and multiplayer games are less likely to work on Steam Deck/Linux due to anticheat issues. So games outside of the top 100 will generally have a higher compatibility rate. For comparison, only about 5% of the top 1000 games are broken on Linux according to Protondb
Depends. I don’t know if kernel anticheats will ever work, but I also would refuse to install any so it doesn’t really matter.