I agree with your thoughts on how the D played overall and that they were a championship unit in 23 for sure, but I do think there is some degree of 'change/simplification' worth considering.
i.e. - we still sometimes, for reasons I don't understand, play a 3 man front (30). When we do, it almost never works, and in fact there were times that was the key adjustment made - i.e. against UGA to start to shut them down. We were running 30, they were killing us, Saban switched to the 40, and we played much, much better. It's been that way for at least 4, maybe 5 seasons now. It's almost always a passing down when this happens, and in the 30 front we pull an OLB out into coverage, but keep both the ILBs in the box, and usually blitz one. So we take our best pass rusher out of the role where he does his best thing, and make an ILB rush which is not his best thing either (or he'd be an OLB). If we stay in 40, we let the pass rusher do his best thing, and we keep the ILB in coverage where he's got a better chance of running with the LB or TE than an OLB does. Let's be honest, our OLBs and ILBs are not really interchangeable. The ILBs are typically 6'2"- 6'3", and 225 to 235. The OLBs are minimum 6'4", and usually 250 to 255.
For all the references to the vaunted 3-4 Over/Under, we really don't run it any more. I didn't chart every play this season, but I have in the past and there were seasons that we literally ran that alignment and grouping a grand total of 5 times, and all were goal line or short yardage situations.
Our base is a really and truly a Nickel. We legit run nickel 70-75% + of the time, with almost all the rest being a dime variant. More often than not the nickel aligns as a 4-2. Sometimes that same personnel grouping runs it like a 3-3, but per above, we don't execute that as well because the 3rd LB in when we do that, is really a pass rush guy we're asking to run in coverage. Who would you rather have rush, Anderson, Turner and Braswell type guys, or Christian Harris, Henry To'o To'o and D Lawson type guys?
So at least in theory, we could drop all the 30 front nickel stuff out of the playbook, not have to learn it, not have to practice it, etc and it likely wouldn't have a negative impact on our overall quality of defense at all. We could still have some blitz disguises where we play 40, but have an OLB drop and an ILB rush and all that fun stuff, but that's different than aligning in a 30, where we've pulled the OLB way out into the flats in coverage...