Do I have duty to love my family?

You don't, even if they are biological or whatever. You can't control your feelings and that goes for your familt as well. If you don't feel love for them, then the question remains... Have they done good enough to deserve this love of yours

You don't owe anybody anything. You are free to do anything you want, but you are not free from the consequences of your actions. So if you decide to distance yourself from your family because of a toxic environment, that's okay. But if there are only differences in opinions, think about it before taking any definitive decision. If you want to lose contact, that's alright, as i said, you don't owe anybody anything. But you may one day need them, or they may need you. Think of that and analize what you would do in that scenario, then try to figure out what feelings you have towards your family