I have gigabit fiber and somehow Xbox Cloud Gaming looks like shit. I don’t know how anyone uses it! (On Ethernet, in LA)
I had the best experience, quality wise, with Stadia though.
I consider myself pretty attuned to (and annoyed by) compression artifacts in streaming video.
I did end up buying an Xbox instead of using Stadia though - I couldn’t get over paying full price for games I didn’t actually own.