I wonder if the universe is trying to push Sophina into taking her sister’s place as the “villainess”. She would have to sacrifice herself but she could ensure her sister lives by becoming the “heroine”.
I took it to be less about jealousy, and more about impostor syndrome. "even a literal child does things better than me. why am I even shouldering this responsibility, all I have done is probably merely to harm my subjects indirectly through my incompetency".
Sophina is actually incredible for surviving this many resets mostly intact. Thankfully going back to the age of 5 allows her personality to change per route without any issues at the very least.