I am an expert at d2 and I have played at every level. But my 1A IQ isn't high.
What I "can" see is that your 4 best DL's are decent at 1A. The other guys are terrible. Forget their total ratings, their tackling and Str are good enough to be pretty good, not great D2 players. And you are only carrying 6 DL's . With a 4-3 I like to carry 8. Ideally, 2 Seniors, 2 Juniors, etc. This to me is the ideal which is almost never practical depending on your situation. Reason I like to stagger it is they lose WE when not getting playing time the higher they are (Senior, Jr. , etc.)
In your case, as soon as your best DL's tire they will replaced by very poor(for 1A) subs. And you will give up rushing yardage. And if you try to make up for that by allowing your starters to get subbed out when they are more tired, then the starters will be less effective and the subs will grow less because of less playing time.
You have to recruit better Interception.