Actually she wants him dead or removed from crown prince position so her child can be crowned なんでもない~
Not at all, she makes it very clear she doesn't care about any position. If you actually kept up with reading, you would know all of this started with her obsession with lee nok's mother's face which she never got over with, and now with lee nok's face who looks exactly like her.
Imagine if the evil step mother found out about plastic surgery,,,,all that just cause she wants lee nok's face bruh