It's just absysmal right now.
GeForce Now - great for shield TV but the big publishers are unwilling to commit to it
XBOX GamePass Ultimate - unsupported on android TV but your YMMV with sideloading and even if you get it to work, 720P only
Stadia - again, unsupported on android TV + general consumer distrust that google won't commit to it.
PsNow - need a PC to stream it to androidTV. The PC interface is rage inducing and there's a ton of shovelware to sift through
...
That leaves local streaming as the local options:
Xbox Series S/X. No streaming to other devices
PS4/5 remoteplay: sideloading needed YMMV
GeForce experience: it works but not everything works smoothly from the couch (computer could be locked, games that lack controller support, etc). I ended going with this option with reluctance.
I think it's safe to say that cloud gaming won't be taken seriously this generation by the big players
I have two shields that are perfectly capable of streaming games. Just offer something and take my money dammit :)
EDIT 1 - seems I should give stadia a shot (I still don’t trust googles commitment level given their track record)
EDIT 2 - PC streaming clearly is the winner (I would agree, as I use GFE local streaming)
EDIT 3 - when is Sony and Microsoft going to get their act together and take TV-based cloud gaming seriously?