I agree to an extent. But I would narrow the majority of the problems to be primarily the front 3 and then Peprah not having the requisite range at his position.
Well to the lead the league in interceptions is huge when you have terrible blitzing and the quarterbacks have all the time in the world to pass.
You can't expect the secondary to pick off every single pass, I don't think it's all their fault. This defense is the opposite of how you would want it.
Most defenses, it's the linebackers and blitzing that do all the heavy lifting for a defense, and then you have to count on the CB's and secondary to get the interceptions. The Packers are the complete opposite of that. The secondary does all the heavy lifting, by getting the interceptions, fighting against deep ball and easy passes. The front 3, and linebackers are absolutely ridiculous. When it comes to running all over the Packers D, I'd say that San Diego showed the way around the league. Just run the opposite direction of Clay Matthews and you can rack up 100 rushing yards easily.
The secondary of this defense is what any defensive coordinator would dream of having, if they had a missing link. 3/4's of the time with a defense, they'll have the linebackers and blitz core but will be missing a good secondary for interceptions. This of course was the problem with the "Dome Patrol" in the late 80's and early 90's of New Orleans. That was one of the greatest linebacker cores of all time, but their secondary was average. Those guys were a damn nightmare to quarterbacks in their short prime, and they finished ranked #1 back to back, but they still were missing good CB's to get interceptions.
Our defense is only 50% complete of a total 100%. They got the corners and lead the league in interceptions, but if they had the pressure to send on quarterbacks, a good linebacker core, and something along those lines, they could go from a worst ranked defense to a top 3, hard to believe but that's how I see it.