most teams have a 3 or 4 deep ...the best teams are virtually interchangeable in their depth
We have maybe a 2 deep ...that is stocked with freshmen...huge fall off.
We have no depth on the D front. None . If depth was not important ...the best teams would not have crazy depth and be known to play 12 linemen a game .
defensive depth issues are most notable late in the season ...due to the physical wear and tear .
This ...coupled with a very young secondary ...is what you are seeing. The only way this can be fixed is through recruiting . Give it a couple of seasons.