Andy Weir's stuff isn't utopian but is obviously very science-positive. I have slightly mixed feelings about Alastair Reynolds' work (I thought Revelation Space petered out a bit, but that Zima Blue is profoundly beautiful etc) but his Blue Remembered Earth trilogy is a very deliberate (dare I say heavy handed) attempt at a more optimistic universe. Going back a little, obviously there's the Culture series which definitely does examine some of the complexity behind a powerful, galaxy-spanning utopian civilisation and its AI attendants, and some of the books are tragic, but I'd definitely live there. More generally, just google solarpunk and you'll find lots of recommendations. I don't know which authors specifically identify with that genre going forward, I've heard good things about Becky Chambers but haven't read any of her books yet.