The butterfly effects would add up and and any zygote formed would not be the hitler-as-we-know anymore, since it would be a different combination of sperm and eggs.
Who needs guns when you got a time machine? Don’t like your highschool bully, just bump into their parents back in time. Or you know, “bump” ( ͡° ͜ʖ ͡°) into their parents.
I doubt that a child assigned female at birth would be as horrible in that patriarchal and misogynistic environment.
Ehh, people are capable of doing pretty nasty shit regardless of sex or gender. But on the other hand, had Hitler not been a cis man, it’d have been a lot harder to get in a position of power that’d enable hitler to do what he did. So I see your point.