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.
But its technically not your timeline’s hitler anymore.
Who knows, maybe this offspring produced by the same parents turned out to be XX chromosomes (aka: assigned female at birth) and therefore would not be in the same trajectory given the extreme-patriarchal and misogynistic society at the time. Or maybe even if he turned out to be assigned male at birth, he would have a slighly different personality that cause him to get shot to death in WW1.
But either way, you still caused your hitler to cease to exist.