I think he's got talent but wouldn't count on him. No matter how talented you are, there's a minimum of physical qualifications you need in order to play modern top football. Not just strength or pace, but lightness, dynamism, overall athleticism.
A player like Pedri is currently cutting it very close, and despite his abundance of talent (a good deal more than Bernal) he clearly has his struggles.
Bernal just doesn't meet that minimum. I don't know if it's genetics or body mechanics or what it is. Some people just have a heavy ass, they move more slowly, laboriously than others. It's not something you can really train away. There are obviously games in which he will be ok, situations that won't pressure him in that way. But long term I don't see it.
Busquets is obviously a reference, but I think he was both more talented and lighter on his feet than Bernal.
