That makes absolutely no sense. Jesus is not the enmity. Jesus is not “hostility - animosity – antagonism”. The hostility, animosity and antagonism come from Satan. Jesus is the seed that crushes Satan’s head.
Then Jesus being a "branch" makes no sense, either.
You don't get to have it both ways. It IS a valid possibility under Protestant interpretive norms. I disagree, but it is valid.
I personally see this as two parallel statements (enmity between The Woman and Satan, and enmity between Her Seed (why on earth would God bother to give the Savior a title drawing attention to his mother) and Satan.