Well there are lots of ecomomists that make excellent points that Germany could’ve paid back the reperations fairly easily if there had been the political will to do so.
If you recall in the Franco-Prussian War, Prussia (soon to be Germany) luimbered France with huge reperations. And the French astounded everyone by paying it back and quick. In fact this jolted the French economy and put France on an economic upswing.
So you can reasonably argue that Germany could’ve paid back reperations and that didn’t shatter the economy.
As for Hitler, well lots of other countries had dictatorships. Notably Italy, Spain and the Soviet Union. So you could’ve even seen a Germany under a dictator but one not so ruthless.
The medical data the Nazis did was so poorly recorded and researched that it isn’t worth much. This has gone down as “people don’t want to use it 'cause of the unethical way it was done,” but it was simplistic and poor quality and outdated even by the 50s.
Hitler’s autobahn was a positive thing.
The problem is almost everything Hitler did that was good, was militaristic in nature. For instance, he pulled Germany out of the depression by military spending. And that is what happened in the USA too. But because Germany was totally devistated at the end of the war, nothing good came out of that spending, as oppsed to the USA which was pretty much untouched by the war so it got rich.
You can find good in anything, so it’s incorrect to say “no good” came from Hitler, but outside of the autobahn it’s hard to find any lasting thing.
Oh you could say thing like the V-2 rockets, which were used as the basis for space travel was good, but there’s no reason to think someone else wouldn’t have thought of it later on. Perhaps you could claim it sped up the process of nuclear power and space exploration but again, there’s no reason to think it would’nt have happened without Hitler or WWII.