This "charisma" you refer to is a funny thing. My impression is that Hitler, just like Trump, said the things that resonated deeply with certain people (gullible racist assholes who happened to also be desperately seeking a solution to their ills).

https://www.bbc.com/news/magazine-20237437

Before WWI he was a nobody, an oddball who could not form intimate relationships, was unable to debate intellectually and was filled with hatred and prejudice.

But when Hitler spoke in the Munich beer halls in the aftermath of Germany's defeat in WWI, suddenly his weaknesses were perceived as strengths.

His hatred chimed with the feelings of thousands of Germans who felt humiliated by the terms of the Versailles treaty and sought a scapegoat for the loss of the war. His inability to debate was taken as strength of character and his refusal to make small talk was considered the mark of a "great man" who lived apart from the crowd.

More than anything, it was the fact that Hitler found that he could make a connection with his audience that was the basis of all his future success. And many called this connection "charisma".

"The man gave off such a charisma that people believed whatever he said," says Emil Klein, who heard Hitler speak in the 1920s.

But Hitler did not "hypnotise" his audience. Not everyone felt this charismatic connection, you had to be predisposed to believe what Hitler was saying to experience it. Many people who heard Hitler speak at this time thought he was an idiot.

"He shouted out really, really simple political ideas. I thought he wasn't quite normal."