Is my preference to live far from my family—due to financial and personal circumstances—considered an act of disobedience towards my father, who wants me by his side, especially since he is unconvinced by my opinion and threatens anger and withdrawal of help?

Filial piety has great merit. So, if you can fulfill your father's wish for you to live close to him, then do so, as this may bring sustenance and mend relationships. Marriage itself is a means of sustenance. However, if you fear financial harm, try to convince your father to let you live farther away, seeking help from those who hold influence with him. If he is not convinced, then there is no blame upon you for living far away, for obedience to parents is not obligatory if it causes harm to the child. In all circumstances, be diligent in honoring your father, visiting him, and checking on his well-being.