Is saying to one's father: "Consider me not your son, and you are not my father" considered an act of disobedience (to parents)?

What you said to your father is an act of disobedience (ʿuqūq). Therefore, seek Allah’s forgiveness, repent to Him, and apologize to your father. There is no harm in disliking the sins and evil deeds that he commits, because this dislike is directed at the act, not at the person. There is no accountability for the heartfelt dislike that a person cannot دفع (repel), but a person is held accountable for acting upon that dislike through forbidden words or deeds towards the father, even if he is abusive or dissolute. Indeed, that does not negate one’s duty of righteousness towards him, nor does it permit mistreating him.