Palia is the perfect game for chill vibes, either alone or co-op

looks like your "home" is instanced and just for you - and then you go out to the "MMO" world.

but even that doesn't sound like "MMO", but now every game where you can see someone random online seems to grab that description.

either way, I think it looks worth checking out, since as a man in his 40's, I am clearly the target audience for happy fun times games like Stardew Valley, Animal Crossing, and Disney Dreamlight.