You know, even after watching the NBA for well nigh three decades, at times I forget how big of a jump it is from college to the pros. Most rookies and sophomores are bad on defense because they've never had to deal with NBA offenses.
Mike Conley is a 13-year NBA veteran and I think if you let him go back to Ohio State right now and play, he'd take them to Final Four in a pinch. Rudy would probably put up Wilt-like numbers in the NCAA right now.
Zion has a lot of practice time to put in before he's not a liability of offense. You're playing with the big boys now.