Here’s a very simple solution:
1. A nine team championship playoff between the conference champions of the SEC, ACC Big 10, Big 12, PAC 12, and the top four CFB ranked teams that are not a conference champion.
2. The two lowest CFB ranked teams of the nine play the second (or third) Saturday of December, and the winner advances to the final eight, who are seeded based upon CFB rank.
3. The next Saturday, seed 1 plays 8, 2 plays 7, 3 plays 6, and 4 plays 4.
4. On the following Saturday or New Year’s Eve/New Year’s Day (which ever is later) the semi-finalists play.
5. The national championship is played on or about January 7, as it is now.
I would also consider ending the regular season one week earlier to give the players recovery time, either by cutting one game from the regular season and/or starting the season one week earlier.
Limit each team to 50 players... this way, the talent would be spread out instead 5 deep on the best teams.