you just listed. Cost and long-term care for injuries are handled through rated insurance contracts. There are massive, massive companies who provide this as a service.
Literally the only issue listed that isn't addressed by existing sports leagues is whether or not class time is considered "working hours". I'm guessing the schools would suddenly just stop requiring students to attend classes. (I'm guessing that most of these guys aren't spending a lot of time in class).
Once again, not saying it's not complicated, but there is an existing model to work off of, whereas NIL is a complete crap-show.