I think a lot of books miss the mark on this by making the shift too clean. A real power shift isn't just the victim becoming powerful and the bully suddenly being sorry—it's the messy, ugly process of dismantling the original dynamic. 'Bully' by Penelope Douglas is a standard rec, but the power there feels a bit scripted, like they're taking turns holding the upper hand according to the plot. For a more unsettling shift, try 'Vicious' by L.J. Shen. The bully's dominance is tied to social capital and family money, so when the heroine starts gaining her own agency, it destabilizes his entire worldview, not just their interactions. The power doesn't neatly transfer; it sort of explodes, and they have to figure out how to relate in the rubble.
I'm more interested in books where the 'lover' part feels earned through that chaos, not guaranteed. The shift has to cost both of them something, or it's just a role reversal, not a true transformation of the relationship's foundation.