I’m not sure at this point if it was reincarnation or second life but it was about the female lead who gets a second chance at life and she ends up with this book that basically tells her how to save the duke and the book is only about him, and they basically end up going through a bunch of trials and tribulations together (she’s also his maid)
Man it’s been a while since I’ve read a queer/bl story where the family part felt natural and actually part of the story rather than it just being there to technically be part of the genre or something