I finally took the time to do this but I can confirm two things…
Retroarch works on Xbox in retail mode…..
i am currently playing Def jam fight for New York … with a GameCube rom that I still had.
it’s currently running at 60fps which is nuts.
I can also confirm that Kodi movie addons work… the interface is slow as shit but they work… I was watching a little nope. The movie does run at 1080p… I do think I need to add a vpn to my Xbox if I want to continue doing this…
But Retroarch is legit working at running.. there is a little trick to doing though.