I had to read mein kampf recently and I’ve been learning about nazism in general and to me it’s just shocking how so little of it makes any sense. It reminds me of QAnon (obviously QAnon borrows a lot from Nazism and is in many ways just a rebranding of it) just in that you look at it and you just can’t even really wrap your head around how someone could even believe this stuff. So were there any academic or other more educated Nazis who tried to fit National Socialism into a larger framework and actually justify it as a legitimate philosophy? Or was it really more of a fringe conspiracy that just took over?
Surely the first name on the list has to be Martin Heidegger here. Certainly amongst the most influential philosophers of the century, if you measure that not just by the philosophers he influenced, but also by those who took considerable effort to disproof him. If you were to list all those names, you'd basically end up with a who's who of 20th century philosophy. Particularly interesting here is how his supporters and critics can't be neatly arranged on the political spectrum. His probably most famous disciple is Hannah Arendt, the Jewish political theorist, whose work became essential to the modern understanding of totalitarianism. Not exactly what you'd expect. They even had an affair, and she brushed off his involvement with the Nazis as a mere personal error of judgement.
Or take Critical Theory and the Frankfurt School. On the one hand, we have Theodor W. Adorno, who was an adamant critic of Heidegger, to the point where his book Der Jargon der Eigentlichkeit criticizing the political language of West-Germany's elites basically turns into one big polemic attack on Heidegger, that stands out from the rest of his works as rather untypical. On the other though, there is Herbert Marcuse, another Heidegger disciple and author of Philosophie und Kritische Theorie, quite programmatic for the School. Habermas called him a Heidegger-Marxist. And then there is of course Heidegger's considerable influence on Sartre and French existentialism, also later on Foucault and Derida. At this point, I think I'm done demonstrating that Heidegger was anything but fringe, so it may suffice.
Another name that comes to mind is that of Carl Schmitt, a catholic conservative political theorist and jurist, who continues to draw attention from philosophical heavy hitters, with Slavoj Zizek the latest addition. His thinking on the importance of a strong central state is seeing a resurgence in China lately, especially since Xi Jinping took power. Maybe not the most savory character, but again certainly not fringe and quite similar to Heidegger in resurfacing at surprising places.
Anyway, it's late and I'm way too tired to even pretend to try to keep up to the standards of this sub, so I just hope this will give you some idea and maybe a starting point for further reading until some actual expert on the matter chimes in.