I don't think it is either of those. He is clearly not dumb nor do I think he is inherently evil. The thing is just that he became a billionaire at 23 and did not have to experience any of the grounding and setbacks that turn someone into a responsible adult.

He is basically a middle-aged college bro that always got what he wanted and never had to ask twice for something.

It's not like he was a decent person before he got rich.