There's no perfect solution, which is why the NCAA kept it as a total no for years. Once you open this box, it's hard to go back.
If I was doing it, I'd develop a farm league of 8 teams of 60 players each. Those 480 players would be 3 classes of 160 players, meaning 160 high school recruits are added each year. They are paid contracts for 3 years, and only three years. No NIL, no education, no nothing. They're professionals at that point. They will get coaching, evaluation, and play 3 years of 16 games, including playoffs. After those 3 years, they can declare for the NFL or they can move on, but 3 years, and that's it.
Meanwhile, the rest of the recruits that are left, get recruited by regular schools and go the regular college route, in which they stay for 3 years, and they get a stipend that is determined by leagues (Much like what Thamel is suggesting here).
NIL's just don't need to be given to individuals. They need to happen as teams, so that the wealth can be spread. And honestly, if I'm a businessman, I'd rather say "Here's a million dollars, let's split it 85 ways, and give $12,000 yearly to each Tennessee player in order to have them sign an occasional autograph, or an appearance for us," than to spend $1,000,000 on a Quinn Ewers who may transfer, or who may end up sucking. And of course, if multiple companies did that, then even if it was only a few thousand dollars, each player would end up making quite a nice paycheck, in addition to what they're already getting through their scholarship.
I don't know. I don't want college sports to be ruined, but I feel like its headed that way. When it becomes all about the money, it's just not going to be the same.