It's more nuanced than you may think. We all know that marx was a jew, but marxism itself is only halfway made up of marx's jewish worldview. The other half of it comes from Engels, who was aryan. This leads to an interesting dichotomy and is likely the cause of marxism's splintering during the early days of the labor movement.
And I can categorize the splintering of marxism into 3 separate categories:
Orthodox marxism. This is the core of what marxism was originally and it has never been particularly successful. The only people who have ever really represented orthodox marxism are anarchists such as kropotkin.
Sorelian marxism. This is where it gets... weird. Georges Sorel was a French heterodox marxist thinker active in the late 1800s and early 1900s. Sorel was unique in combining marxist theory with blatant reactionary and monarchist theory. This is the variant of Marxism that spawned mussolinis fascism and therefore every third positionist movement afterwards. It played a smaller role in the formation of the 3rd type of marxism:
Leninism. Somewhere between sorelianism and classical marxism. Has more reactionary traits than orthodox marxism but fewer than sorelian marxism, and it was inspired by both. Leninism would spawn multiple cadet ideologies like stalinism, maoism, juche, etc.
What is important to understand: it can be valuable to cherry-pick the theories of Marxism in the same manner as Georges Sorel or Mussolini. Why? Because marx wasn't wrong about anything, we are currently living in the era of the fulfillment of what he wrote about in Kapital. The issue with marx was in his solution, but his and engels' predictions are very much true. The wise person sees the writing on the wall and learns from this. When you read marx you understand the problem, but it should be up to you to decide the solution for the problem.
Sorel, ironically a heterodox marxist, was the inventor of the blueprint for fascism. And fascism was the blueprint for national socialism. We also have other movements like the national syndicalist Falange, which is undiluted sorelianism. None of this would have happened if sorel never wrote any theory, and if he hadn't been a once orthodox marxist who dabbled in reactionary beliefs.
That being said though, there are some things about sorel that are kind of jarring and odd by modern standards because sorelian thought is effectively the evolutionary transitory period from marxism to fascism. Such examples include his support of Lenin and mussolini simultaneously, or his praise by both Lenin and mussolini as well. 3rd positionism by this stage obviously wasn't fully developed and completely coherent yet and it still had a lot of vestigial leftovers from marx
from what i understand, mussolini's trains ran on time, but he had no loyalty to his people and worked with whatever mercenaries (metaphorical) would serve the state the best - you could almost call it a fluke that he happened to be a competent statesman. marxism is mostly insane ramblings to justify jewish genocidal tyranny... what's WW2 Germany got to do with either of those?
What hitler took from mussolini, and in turn what mussolini took from sorel, was organization, glorification and use of justified violence, hostility to bourgeoisie democracy, and the theory of mythos leading to a cultivation of power (this was also shared by Lenin as well), they also both shared collectivism and identity. What they both agreed on, but did not take from sorel, was class collaborationism. Where they differed was mussolinis belief of national identity and hitlers belief of racial identity, although mussolini would later on believe in racial identity as well.