Hitler was guilty of many things, including foolishness, but to label him a fool is so simplistic it's comical. Seems to me the specific references here would make him guilty of hubris, egotism, failed political gambits, not being a fool. A fool does not manufacture one of the greatest Machiavellian rises to power ever.
Invading the Soviet Union was the act of a fool, it wasn't a "failed political gambit" - it wasn't political, it was genocidal, and suicidal
Though to Hitler, doing something suicidal was better than doing nothing at all - like Trump, and Qewanon MacKenna, and that repressed simpleton on this forum, he was obsessed above all with people talking about him, and he wanted people to talk about him forever
Invading Russia wasn't something done on the spur of the moment, surprise at Britain and France declaring war displayed a child-like delusion
He was also lazy as fook and surrounded by yes men
What he was certainly right about was his belief in the power of propaganda, rhetoric, charisma, grievance, notions of revenge and all out violence to bring many millions of people with him
Many millions of deluded fools - the same sort of people who exist everywhere right now - in the US, Britain, Russia, India, Ireland