Is it obligatory to maintain kinship ties with an aunt who does not pray, smokes, drinks alcohol, does not inquire about her family, and from whom other abuses are experienced?

If boycotting the aunt due to her sins leads to her repentance and return (to righteousness), then this is permissible and مطلوب (desirable/required). However, if no benefit results from the boycott, then it is obligatory to maintain ties with her, even if she boycotts or wrongs (you), because one sin is not countered with another. The aunt must fear Allah and repent from abandoning prayer, smoking, and drinking alcohol, and it is not permissible for her to cut off kinship ties with you, because maintaining kinship ties is obligatory.