My playoff plan.
12 teams.

Committee rates the 10 conference champions 1-10.
1-4 get a first round bye and home field.
5-8 get home field.
9-10 are placed in a pool with the top teams that are not conference champions and rated 9-12 and seeded into the field.

Basic principles, winning your league MATTERS all home field slots are guaranteed to league champions. Outstanding at-large teams ought to be good enough to overcome traveling to a lesser conference champ. Exception. Any independent in top 8 gets treated as a champion and at-large pool shrinks to one.

Example from last year using Massey composite in lieu of committee where teams aren't rated in CFP poll
1 Alabama
2 Clemson
3 Notre Dame
4 Oklahoma
5 Ohio State
6 UCF
7 Washington
8 Boise State
9 Appalachian State
10 UAB
11 NIU
At Large 1 Georgia

1-4 home plus bye
5-8 home
9-11 + Georgia rerated 9-12.

Playoff field
Boise State hosts Georgia, winner travels to Alabama
Washington hosts Appalachian State, winner travels to Clemson * Note App would have hosted but for Notre Dame placing in top 8
UCF hosts UAB winner travels to Notre Dame
Ohio State hosts NIU, winner travels to Oklahoma.