unhinged theory incoming
it's weird that the nobles instantly accepted and praised sophia as the rightful heir to the kingdom without a fight - that she's so universally, almost unnaturally beloved by the people. So i started thinking:
Sophia is actually going to be the main antagonist that used some kind of "charm magic" to manipulate the entire kingdom to be under her thumb. She was said to have brought peace to the kingdom through the "persuasive power of her kindness" which could sound a little ominous if you look at it a certain way. Remember that Sophia was also adopted, not born, into the royal family as well.
Maybe Olivia is the only one who passively resisted it because of her own unnatural magical aptitude. It would also explain Sophia's somewhat unnatural degree of kindness towards Olivia if there's an ulterior motive behind it - Olivia outright spurns and scorns Sophia, who seems unbothered and continues to try to persuade her into friendship. Sophia could just be a saint... or maybe she's trying to win over the person she can't magically charm onto her side.
she also could be seen as the one who caused the isekai thing too back in chapter 1 - the dialogue box specifically asked "Sophia wants to meet with you. Will you go?" which could be interpreted such that Sophia is the one who instigated the entire incident.
also, in a meta sense, it's kind of odd to me that the author seems to be building up Olivia as the main heroine of the story and not Sophia. We're learning so much about Olivia's inner struggles, her history, etc... and yet almost nothing about Sophia beyond the surface level qualities that pretty much were shown since the first chapter, despite the first volume focusing solely on Sophia. The above would also explain why the story is going in that direction.
On one hand: Ok, not a never-heard-of trope but it would make the story more interesting
On another hand: Noooo, don't do this to my good ol' sol harem
