The misconception here is that large amounts of cash are just now being added. That's always been a fact of life in high level college athletics, now it's open, we gave an OL recruit 50k and he chose Georgia just a couple years ago.
There are contracts signed, as long as the player meets requirements regarding public appearances, they are good and will get their full pay. They very likely don't have performance clauses. NiL companies have to carefully select athletes, just like with any business venture risk/reward is factored into it. The closer to a "sure bet" you are, the more money you will command. It's no different than drafting someone #1 overall, you have done your homework and tried to analyze to the best of your ability, their future impact. Having a potentially great UT QB in the fold to do public appearances/advertising for your company in Tennessee, is a huge deal. Multiple local companies signed Peyton as soon as he left school. He did radio and tv commercials for years after. Nico comes here, puts up numbers like Hooker has put up, gets UT winning 10+ again, he will be the hottest thing in the state. Companies that have contributed to his NiL package will make out like bandits.
Football is more popular here in the state, it always will be. So they command higher money. Former football players are much more celebrated than former basketball players by the majority as well. If you asked people who they associated most with UT athletics over the last 30 years that weren't currently playing, among players you will hear Peyton, Jason Witten, Heath, Tee, Al Wilson, Peerless Price, Casey Clausen, John Henderson, Jennings etc etc before you hear any basketball players among the majority of fans.
The players understand that some people have more value than others. Do you think Mahomes' teammates secretly seethe behind the scenes that he's making 10x what they are? They realize that by having a great QB, they will win more and eventually that will mean more money for them. A rising tide lifts all boats and all that.