@ActiveInternetSandwich
You don't recall that the prince himself is at least as wicked as Lilia, if not moreso? He abused his fiance, stole her accomplishments and property, is a greedy, self-interested bigot with an inferiority complex who shirks his responsabilities, and so forth. Lilia at least pretends to be good, the prince mostly just flaunts his authority outright, while using it to shield himself. The whole thing is very peas-in-a-pod for either side.
The entire theme across the manga has been that the original visual novel that this world is based on, essentially had wickedness [ie, corrupt human authority figures] win over good [ie, peaceful monsters], and that the MC here has slowly realized that distinction between her new reality and the facade the visual novel presented, wherein it presented the protagonist and her side being good (despite the VN dropping hints that such wasn't actually true). Even just a bit ago, the MC was noting how Lilia abused Claude's feelings in the visual novel, deliberately provoking him against Keith.