Edit: Mid to late 40's those PB are useless, by 1944 5 KGV, 2-4 Lions, Vanguard, 2-3 Richelieus exist that can catch them and destroy them with ease, with more on the way, rather than 1939 where there were merely Hood, 2 Renown, 2 Dunkerques that could do it and will still be around, so 17+ PB killers as opposed to 5, not good odds
The large surface raider appears to be a 1920s to 1930s solution when submarines are still mostly blind, mostly slow and mostly vulnerable, before radar one needs a flock of aircraft to scout at any distance, speed to outrun or bigger guns to outfight Cruisers, and tonnage for habitability, fuel, stores and workshops to be independent. Now I believe these ships became political weapons at bottom, but again are a case of Germany getting the right ship after its useful era past. These are in my mind what the Imperial Navy needed, perhaps useful post-war and in the interim years before 1939.
In theory a very fast heavy cruiser, say 10 to 15,000 tons, might slip in and extend this life for the mission, but I think it becomes the surface component to the U-boat war, and still vulnerable to any opposing surface fleet since the biggest issue is that Germany must break out of the North Sea to ever contest any enemy. That should have circled them back to a cruiser submarine, far faster in transit or stalking, far better underwater when evading or transiting near any air cover, and able to stay out on station once it got out on the shipping lanes. Its biggest weakness being finding targets.
Germany should have been earlier to pursue RDF and hunting for radio chatter, an antenna is easier than getting an airplane on a sub and Germany should have seen the value radar has for a submarine searching the expanse of ocean at night too. And I wonder why no one thought about jamming radios on target shipping, that seems to be a necessity for some lone hunter to delay the hounds. Germany's geography almost mandates that submarines are its only hope getting out beyond the British Isles, its surface Navy is best used as the bogeyman to tie down the RN on big ships and ignore escorts. If I were to reform the KM or either era I would get them to admit the capital ships are a bluff and pursue mine warfare, submarines and aviation to actually fight a winnable naval war versus the only opponent that matters, the RN, strangle the coastal trade, sink ships at anchor, blockade from the Western sea lanes. A decisive battle is propaganda to lull the British into opposing the wrong thing. Nazi Germany did not have the time or I believe leadership to do just that, so perhaps it is moot, but grist for our ATL mills.
So for my ATL thinking, I want a Cruiser that can go hunting on the open ocean, faster than anything afloat, only better armed than the average AMC or likely trade protection cruiser, likely biased to several scout airplanes. Maybe a sort of
Tone-class looking thing, less guns, maybe a light torpedo optimized for anti-ship kills, using more tonnage for endurance, and the earliest Radar and ESM outfit technology permits. Still a dead end but between 1919 and 1939 it has promise and can be paraded as Germany's foreign station cruiser. It might leverage into a supporting role for a better U-boat campaign after that, but then I think it needs to consider AA warfare and radar to warn against aircraft. It will pursue a dangerously exposed mission but Germany has the deck stacked against her anyway.