Rather my entire point.IDK how you avoid the Hipper and Scharnhorst classes? (and guess you could include the GZ carrier) their Plan Z returned to diesel power, so almost the whole of the WWII fleet can be considered an interim step?
possibly the carrier project could mirror the Italian conversion of an ocean liner? (the SS Columbus was available)
the existing Pz ships had a known rebuild, replace the 150mm & 105mm guns with 128mm ones, with some changes to the hull it was projected to increase their speed. just build more of those ships with 8" guns to utilize their heavy cruiser allowance instead of the Hipper-class? (so the original 3 + 5 more with 8" guns)
at the top of the heap just build another pair of Twins with the 15" guns? certainly they could arrive faster than the Bismarck-class?
What purpose did the KM capital ships fulfill? They were never going to be able to fave off with either the Royal Navy nor the USN. They were at least 10 years , more likely 14-15 from drawing even with either potential opponent even if they simply followed the LNT II replacement schedule. Tirpitz, the second ship and final build in the Bismark class took 50 months (4 years, 2 months) from first steel to commission, or roughly the same time as a KGV. The Alabama, final ship in the South Dakota class took 30 months (2.5 years), Washington took 35 months while Iowa took 30 months American yards could put two superior (markedly superior in the case of the Iowa class) into the water for every hull the Reich completed.
The KM would NEVER had been large enough to go toe-to-toe with the RN or USN battle line much less the combined Anglo-American fleets. Same went for carriers, except much worse. Not only was the KM starting from nothing, meaning the didn't even know how to operate the damned things, the only deck they came even close to completing, the GZ was nowhere near close to even being completed, much less in commission 34 months after first steel (at a guess the ship would have taken around 48 month to be ready for sea trials). The Americans were punching out Essex class carrier in under two years a piece (CV-12 USS Hornet, went from keel to full commission in FIFTEEN MONTHS), and had half a dozen yards that could build them.
Anything the Reich built over 15,000 tons was a VC or a Navy Cross waiting to happen. Utter waste of material, skilled work hours, and eventually brave men.