Works great out of the box. Never installed Cryoutilities or have any issues with Rockstar launcher. I've currently clocked 25+ hours in the game, so far no issues except on 1 occasion where I assumed it was because of resuming the game from sleep, after a while the game started stuttering very badly. Restarted the game solved it.

KylanH posted his settings, I took some of them and lowered them to my liking accordingly. So far it plays great with most of the time 40fps.

Can't comment much about battery life as I played my steam deck plugged in.