You are flat out wrong. A defense and dline as bad as you imply has no chance to go 23-5, 7-2 against P5 teams. 3 wins against top 25 teams. Not wins against teams that were ranked at the time of the game, but 2 teams that were ranked year-end last year (one top 12) and a team that after the loss is still top 17 this year. The defense dominated Utah last year. The defense was great against Baylor this year. The defense was missing 2 starters and struggled against Oregon. The defense is not great. The defense is probably not above average. The defense is much better than you imply. The vast majority of teams the last 3 years struggle to score against our defense. Score differential and wins are the 2 most important statistics in football. BYU dominates in both statistics the last 3 years. Defense is a significant contributor to dominating in the 2 most important statistics in football.

In the last 3 seasons (28 games) teams that scored more than 21 points (only 10 teams - only FIVE of 28 scored over 27 points):
This year: Oregon
2021: UAB, Virginia, USC, Baylor (one of the 2 games, did not score over 21 this year), Boise and USF (barely and won one of the 2)
2020: Houston (barely - still won), Coastal (barely that was on almost zero prep time - this loss was primarily on the offense being inept), UCF (barely and we won).

If you are setting the bar at the defense needs to keep teams under 21 (21 or fewer points scored against 18 of 28) or 27 points (23 of 28 scored 27 or fewer points), I think you are misunderstanding football.

Again the D is not great. It is much better than you imply.