It's going to be messy, no doubt. But there are structures and guardrails in place to avoid some of the problems you mention.
Here's one: "Student-athletes may hire an attorney or agent only for NIL activities. Student-athletes continue to be prohibited from agreeing to be represented for future professional athletic contract negotiations. Anyone assisting a student-athlete in negotiating NIL agreements must be registered as an Athlete Agent with the Missouri Division of Professional Registration, and the University of Missouri Professional Sports Counseling Panel.
A few more rules:
"Missouri State Law (effective August 28, 2021) prohibits all University employees from compensating or causing compensation to be directed to a student-athlete, a prospective student-athlete, or their family members for NIL activities. While it is permissible for a booster to compensate a student-athlete for NIL activities, University employees may not be involved in arranging NIL activities."
" As long as University staff member is not involved in arranging for the promotion, it is permissible for a booster to contract with a student-athlete for NIL activities."
"Student-athletes are required to disclose all NIL activities to the Athletic Compliance Office before they occur."