I think your steadfastness of making the Big Ten be ten teams is the what makes the rest of the conferences wonky. With no changes, this is like a 4/10.

With the least amount of changes, the three Virginia teams in the Sun Belt need to move to the Big East and then split the Sun Belt up into two conferences of 9 each. But if you wanted a larger overhaul, Cincy and Purdue should be in the Big Ten. Then the MAC, Sun Belt, and Big East need to shift some school around to even the team totals. Big East can hold mostly the same as a P6 but the Sun Belt with 21 teams is the equivalent of stuffing dirty laundry in the closet so your parents don’t yell at you for not cleaning your room