That’s a great question that I don’t know how to answer because I haven’t gotten there yet.
What I can tell you is that in this version (no matter which way I go regarding her parents), Kylo never mentions that he wanted to kill her as a little girl, only take her. You can’t do that in the movie because of how difficult it would be to change those lines, and as a result the idea that he always wanted her dead works best for the movie. But this is a different circumstance.