The P4 conferences will decide how much money to throw into the revenue-sharing pot.
The $20M per school number is not set in stone. Most athletic departments don’t make anywhere near that, after expenses.
I expect that some schools will cut non-revenue sports and get rid of some mid-level administration positions to ease the pain.
UCLA, for example, has 26 sanctioned sports and a $100M debt. For 6 years, $10M of its Big Ten distribution will go to Cal. UCLA is one that may eliminate some programs.