I'd like to second the Culture, but just to add (minor spoilers ahead) that it's also a distopian depending on your point of view, which makes it even better.

In the Culture all real agency humanity has is lost to machines (Minds).

Humans have about as much say in important matters in the Culture as dogs do in ours, when anything really important happens (e.g. the events of Excession) they're not even involved.

For any individual human it's a utopia, I'd probably prefer to live in the Culture, but whether it's a good thing to aspire to is something the reader needs to decide for themselves.