Disagree. Yes they can do something about the NIL. They have every right in the world to define what an amateur is or isn't. They can't keep kids from getting endorsement money, but they can declare that if they do, they are no longer amateurs. This ability would be contingent upon their eliminating any rules limiting their ability to turn pro. The greedy idiots that run college sports have historically wanted their cake and to eat it to. They force kids to college where they can't get paid for play. This is wrong. However, if you get out of the business of screwing kids and making them work for free, you can simply reserve amateur athletics to the kids that are willing to exchange a free education for participating.
If a kid is good enough to go pro or talk someone into giving them an NIL deal in or out of high school, fine and good on them. We all know this will quickly dry up as the only reason these NIL deals exist is to get them to attend a particular college. It is pay to play.
If you want to stop it, just stop it. Universities have to just quit screwing and exploiting kids for profit and live with playing the games with kids that are willing to play for an education.