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.
Reminds me a bit of the setting for the Red Alert series of games. Although there they actually go back in time and kill Hitler so different from the scenario in this post but the possible alternate timelines are fun to think about.