There seems to be a disconnect here about what NIL is.
While athletic programs (specifically football, and to a smaller extent men's hoop) benefit by keeping and attracting players via NIL deals, NIL deals are, by their nature, financial agreements between athletes and third-parties -- not between the schools and the athletes.
Opposing NIL freedom for college athletes, the NCAA argued that it had the authority to ban such deals because they arose from the fact that the athlete was in position to receive these deals because they played for Bama in football or Kentucky in basketball. Among other things, the NCAA argued that it was in the public's interest to allow the NCAA to ban or regulate NIL deals because without NCAA oversight, competitive balance would be destroyed, NIL deals would not be fairly administered (as in male athletes getting paid more) and that it violated the founding principle that college athletes are amateurs. The Supreme Court rejected those arguments and ruled that the NCAA can't stop college athletes from negotiating NIL deals with these third parties.
In light of the NIL ruling, schools, conferences and the NCAA can not:
- Cap the amount an athletes receive
- Act to ensure that male and female athletes receive the same amount
- Regulate the NIL deals in any meaningful way
Schools are pretty much limited to reviewing the proposed NIL contracts with the athletes to ensure they comply with applicable law and don't violate the remaining NCAA rules which are in place. While there is no doubt that NIL has been predictably perverted to favor schools with rich boosters as a way to pay recruits, potential transfers and their own players to help their favorite college program (typically football), the essential purpose of NIL is to allow the individual athlete to exploit the available market to maximize his (or her) value. This never was and never will be about making sure all athletes (male or female; football or cross country) get paid a minimum amount or don't exceed a maximum amount. So, there will never be a cap, and there will never be a system to ensure that there is equality in pay.
If Jeff Bezos wants to pay only the white male athletes at Princeton (his alma mater) for some BS Amazon promo gig, he can do that. There is nothing that the NCAA, the conferences or the schools can do to stop it, other than to shutdown their program.