Is a daughter's abandonment of her father—who harms her with sorcery and uses her for his own purposes—considered an act of disobedience (ʿuqūq), and will she be held accountable for it, and what should she do concerning him?

Sorcery is a major sin and may amount to disbelief (kufr). If your father is a sorcerer and you fear harm from him, there is no blame upon you for boycotting him and abandoning him. Marriage is not valid except with a guardian (wali), because the Prophet, peace and blessings be upon him, said: "There is no marriage except with a guardian," and "Any woman who marries without the permission of her guardian, her marriage is invalid." If the guardian refuses to marry you off or becomes a disbeliever, guardianship transfers to the next in line. However, if you are in a country that validates marriage without a guardian, then your marriage is valid. Filial piety towards a father is not negated by his injustice or disbelief, for Allah Almighty says: "But if they endeavor to make you associate with Me that of which you have no knowledge, do not obey them, but accompany them in [this] world with appropriate kindness." So strive to be dutiful to your father, treat him well, and advise him in a way that does not cause you harm. If you fear harm from him, there is no blame upon you for not visiting him, and supplicate much for his guidance.