On Carriers vs BBs, historical purist would say that BBs were becoming obsolete in WW2.
I’m pretty confident you don’t need autokill A6 D6 but only A5 D5 to get interesting results against DDs.
Also, 2 hits should be considered.
Loosing carrying capacity, is not easy decision to make compared to tipping BB.
10 Carriers A0 D2 C16, 2 hits with 20 Fgs A3 D4 C10, against 18 BB A5 D5 C20, 2 hits
Carriers on offense get no chance to survive.
As far as I can try various combinations, even on defense, full Carrier is not better against BB A5 D5, 2 hits.
There is probably a mistake in your simulation, is it really:
10 Carriers A0 D2 C20, 2 hits with 20 Fgs A3 D4 C10, against 20 BB A5 D5 C20, 2 hits?