All are going to be fine academically.
I have visited all 3, & live close to Ann Arbor.
Los Angeles and its lifestyle & attitudes are loved by many & hated by many. If the whole SOCAL/Hollywood vibe really appeals to you, then USC. It’s no accident that so many teen actors & offspring of actors end up there.
Michigan is a blend of smart/affluent frat types & edgy/political/artsy types, with both groups being very confident. I’ve seen few campuses where everybody seems so confident. It doesn’t feel very Mid-west, perhaps due to the presence of lots of students from the coasts. Lacks the humility & kindness that is present on many other Mid-west campuses. Lots to do right off campus. Off-campus housing tends to be pretty run-down. Despite prominence in several sports, doesn’t have a jock vibe to it.
UNC seems like a smallish traditional public university that suddenly expanded past what it was meant to be. So the little business district just off campus seems small & quaint compared to Ann Arbor. And a whole bunch of newer buildings fan out from the old part. Enthusiasm for the basketball team seems to be the dominant emotion. Vibe from people seemed to be nicer than at the other 2 schools you are considering. This is the one I would pick. I’m a veteran, and if you are like the guys I served with, you will fit in here best.