I replied this in another comment but yeah, sort of:
So the magic exclusive to the royal family also makes them instinctively love each other, so when the redhead princess stole her magic, she also took her chance to be instinctively loved AND was making them love her instead. That kind of explains how they adored her in the novel timeline even though she's not a good person vs not even liking her now.
Still, she (MC) noticed the father/king must have known she was the real daughter in the original timeline, yet was still rejected. Even if her magic was completely drained, he could tell it was hers. I don't see how can one redeem from that, even if I feel sorry for him rn.
Oh wow he knew it was hers?? That means he knew that red head stole it and still rejected her
I think there was some kind of black magic brainwashing in 1st timeline. It's impossible for the emperor and the prince to do what they did with the personalities they have in 2nd timeline. And I don't believe their personalities changed