It works Just Fine(tm) (with fiber internet) but guess what's missing: a lot of AAA titles.
So yes, there's a problem with cloud gaming.
Not sure if it's mine or theirs though. I don't have a gaming PC right now, only a PS5. Since we're speaking of ActiBlizzard, i maybe would try Diablo 4 if it were available on GeForce Now. But it isn't and I won't.
Incidentally, I doubt there will be a console Diablo 4 for the PS5 either. They were too far into the acquisition process to not dump non Microsoft platforms.