It's a bizarre tension, isn't it? The typical romance novel clash is about trust or communication, but with a yandere, the fundamental conflict is whether the character's identity can survive the relationship. The 'romance' is a cage gilded with affection. I once read a webnovel where the male lead was this brilliant, gentle pianist, and his yandere girlfriend meticulously isolated him from everyone who 'distracted' him from his art—which was just her. The compelling part wasn't the stalking or threats, but watching him slowly realize his music was dying because his world had shrunk to just her approval. The conflict becomes a quiet, horrific erosion of self.
That said, it often fails when writers treat the yandere's actions as romantic grand gestures rather than profound violations. The tension evaporates if the obsessed character faces no real consequence or internal struggle. The most gripping versions I've seen make the 'victim' character actively complicit in their own imprisonment, craving that intense, exclusive focus even as it destroys them, which is a much darker and more fascinating romantic conflict than a simple chase.