What kind of stuff is he into? My son loves simulator games like…
- BeamNG Drive - better with a wheel but very playable on controller.
- Snowrunner
- American truck simulator
- Farming simulator
- Construction simulator
- Lawn mowing simulator
There are a lot of good kart games on PC also, though I will say that my favorite - Sonic Racing Transformed - is much harder than Mario Kart.
Minecraft Dungeons is basically Diablo for kids.
Minecraft is good but I also like Dragon Quest Builders.
I don’t use Windows at all, and have had the issue I mentioned for Skywalker Saga both on Steam OS and in Fedora on my laptop.
It does only occur in split screen though.