>>18124937 (OP)
Not to sound like a liberal, but Nazism was genuinely a delusional almost religious worldview that led to terrible decision-making, especially in the later half of the war.
German technological superiority early on created and justified notions of German dominance and made them feel invincible. They viewed the Americans as "a nation of shoemakers" and the Soviets as an ass-backward dysfunctional state of human animals held together by a civilized Caucasian strongman that would fall apart in a single strike.
Honestly Hitler's overarching command that historiography blames for losing on the Eastern Front actually led to a lot of success early on, especially in France. He wasn't stupid like many post-WW2 Wehrmacht generals tried to paint him as, but he certainly began to go off his rocker by the end. It was just fundamentally Nazi Germany's goals of dominating the East and underestimating the USSR that led to its inevitable defeat.