Do you at least remember her hair color cause theres a few different stories that meet that description?
I remember her hair was white/silver then her dad is kind of like an archduke or something.
I know a few that kinda match
Daughter of the emperor (her mom died and her dad neglected her for a few years, but grew to like her), the duchess and contract princess, and the saintess became the grand dukes daughter. If the dad also has silver hair then maybe it's the saintess became the grand dukes daughter.
I only remember a child (girl) was left by her mother to a family that mistreats her. Then when she was around 5 her father suddenly appeared and claimed her. (Something like that. I'm sorry if my English is confusing. Please help.)