Messi might be technically better but I have no doubt who is the better player overall - Ronaldo easily.
More CL, titles in multiple leagues, major international wins.
Messi for Barcelona is out of this world but Messi for Argentina is no where close. So how much of his superlative success is thanks to the system? Still no doubt he's a great great player but there is a drop.
For Ronaldo, he's done it in multiple teams, in different leagues, and his performances don't drop when he's playing for Portugal. Today he almost singled handedly dragged the team through. It is much clearer to me that Ronaldo's success is less reliant on others.