No Man’s Sky - One of the most beautiful games out there imo, and has vastly improved since its disasterous launch. Warning this one does require an internet connection (actually for a good reason) but you dont have to interact with anyone, and it’s difficult to even encounter another player in the wild outside of the Anomaly hub and campaigns due to its sheer size.
Project Zomboid - Even if you have zero interest in zombie stuff it’s still worth a shot. Has a massive detailed world based off Midwestern towns in the midst of a zombie apocalypse. It’s still in development so there’s some noticeably unfinished aspects, and they’ve only just begun to add non-zombie NPCs.
It’s also a massive risk when even the advanced ones have a high rejection rate of around 44% that’s never talked about, and don’t have nearly as much fine control as the media makes them out to be on top of being uncomfortably heavy for some people. While some do like them, a lot wind up preferring simpler ones or none at all.