I dunno, I felt this ending is pretty fucking complete. Spending a lifetime stuck in a transmigration doing menial labour and being impoverished is way better a comeuppance than offing her and sending her to jump into another story to enjoy. The husband has also been so thoroughly done over that he's finally become a rather decent person, even if it's because his mind is kind of broken.
Compared to orchestrating people's deaths, possibly in an unnecessarily elaborate manner, this ending is far more skilful because she made sure neither of them escaped being put in their place through suicide. They must live with their failure.