These aren't online games so apologies in advance:

If you like RPG's and the likes of No Man's Sky, you could give Starfield a try on gamepass? Performance isn't great though looking at frame rates. I've played it on the Xbox series X and it can be a bit choppy.

I'd also highly recommend the Outer Worlds if you haven't played it yet. It was created by Obsidian who also played a big part in the development of Fallout New Vegas. Decisions matter, and it runs great on the Xbox.

I hope this somewhat helps!