I think it's quite important to remember that the best thing to do would be just making sure that he would be not hurting the team. You could end up with something much better if he was called but not played, it would be like a veteran legend out there helping the players psychologically at the very best case, but not playing.
I think Ronaldo signing up at Saudi Arabia was basically him retiring of high level competition.
There's no chance he's even called to the next World Cup, even if he wanted to.
Even in Qatar he was substituted and the substitute played way better than him.
There's only downhill from now, getting older and playing for years in a lower quality competition in Saudi Arabia. Not a chance he plays the next world cup.