One side point: There was absolutely no way Germany could win the war. None. He could have avoided a two-front war, done everything right, and he still would have lost an all-out conflict.
Many people have this idea that Germany was a collossus on par with the United States. It wasn’t. Germany was simply the benefactor of U.S. isolationism, pacifism, and distance. Once the United States entered the war, Germany was finished. It was just a matter of how long it took.
America was still ramping up for war in 1944, when it realized that Germany was almost finished and started slowing wartime production. Even so, the U.S. was cranking out an absolutely astounding amount of weaponry. For instance, in 1943 alone, the United States produced more tanks than the entire world inventory of all tanks created since WWI. And even then, the U.S. had so much resources that it never even went into a recession once during the war - the only combatant to pull that feat off. And the U.S. was still investing in new factories and production lines, meaning production could have increased for years and years.
In comparison, Germany was having to devote all of its industrial effort to building weapons - there were few resources left over for new factory construction. So Germany was pretty much at its peak of production. The U.S. wasn’t even close.
In addition, U.S. troops were virtually unscathed. Combat losses were a fraction of what the other nations were enduring. As a result, the U.S. still had the vast majority of its manpower intact, while Germany and Japan were drafting children and untrained persons.
My guess is that if Hitler had made all the best, strategically sound moves, the war might have lasted until maybe 1946 or 1947. But it still would have ended in victory for the allies.
Given all that, it seems clear to me that Hitler’s biggest blunder was in having the U.S. get involved against it. He should have started calling for a peace treaty very early on. If he had attacked Russia only, and appeased Britain and western Europe and the United States, he might have had a chance to grab territory and then bargain a truce.