Whatever you’re feeling, it’s all valid. Nothing is ever really black or white, and you don’t have to try and keep your emotions in clearly defined boxes. Just feel what you’re feeling, acceptance is key. Having conflicting emotions is a common and understandable thing.
For a more personal opinion: this idea that someone being related means you owe them something… well, frankly it’s asinine. We don’t choose our blood relatives, we get stuck with them. Some people win the family lottery, others get stuck with a bunch of assholes. Take the whole blood thing out of the equation, is what I’d say. Missing what you might have had is only human, but separate this from the people they actually were. I guess, ask yourself this: if you weren’t related to them, would you have chosen to have them in your life at all? Your real family is the one you choose. Some people just really aren’t worth your time, even if only because you have to protect your own mental health and happiness.
In your case, if I understand correctly, you’ve already decided not to have them in your life. Maybe it’s just that the finality of death makes you doubt your own choices in this? I’d say trust your instincts and the choices you made. We cannot control or change other people, only the way we respond to them.