I don't know if this would work but since these guys want NIL money, give the player half of the cash when fall training camp opens up. The other half of the year's payout is kept in reserve until the season is totally over. If they don’t play the whole season due to non injury causes, they don’t get the rest of the money. Pretty basic; no work, no pay. Just like any other job.
The same goes with the coaches. They can take a job at another school starting after the season is finished. During the year they are obliged to work solely for their school. Ex.-Manny Diaz stays at PSU until tonight. Then he can start working for Duke.