This year, the Cotton Bowl is a playoff bowl. Normally that is an at large bowl. Suppose that Ohio State makes the playoff, but that every other team in the Big 10 is ranked 13th or worse somehow. The Big Ten still sends someone to the Rose Bowl. It's the contracted bowl. That's how UVA played in the Orange Bowl a while ago. They were not top 12, but they were the backup for the ACC. No at large team was taken.
Long story short, in 2022, the only NY6 bowl BYU is eligible for (without being in the playoff) is the Cotton Bowl. Even if they are ranked 7th or 8th next year, the 5 and 6 teams (say Cincinnati and Notre Dame or some really good Big 10 team) could potentially take the Cotton Bowl slots. All other bowls have P5 contracts and BYU will be excluded.
Ranks like the following would exclude BYU from the Cotton Bowl in 2022:
1. SEC
2. Big 12
3. Big 10
4. SEC
5. G5
6. ND
7. BYU
8. Pac 12
9. Big 10
Or
1. SEC
2. Big 12
3. Big 10
4. SEC
5. Big 10
6. Big 10
7. G5
8. BYU