It sounds like you are struggling with how your parents and the rest of your family treat you.
Does it make it better or worse if you were indeed their child?
In my mind, blood means nothing. Blood might be your starting place, but you can choose to keep who you want at any time. I only associate with people that do not mistreat me. I was NC with my dad until he died. He treated me like shit, so one day I refused to give him the time of day.
My ex was also horribly abusive to me. When I decided “no more,” he got no special treatment from me either. I got a restraining order against him, like I would for anyone that would try to physically harm me.
Holding on to the past and keeping score isn’t helpful for you. It’s ok to remember it as the reason why you wouldn’t talk to them (or gray rock if you must still associate), but to wish the score was settled? It is a burden on you. Treat yourself with the dignity you deserve, let it go, and heal.
It is not easy, but you are worth this work.
I realize that you see things that planted this seed in your head. I am telling you, that is not really the root of your issue.
What does matter? The people that you do choose. The things YOU decide are important.
Believe me, I know this. I have been mistreated for my childhood and early adulthood. I always wondered what I did to deserve it. Truth of the matter is, I was never likely to find the answer. I could spend a whole lifetime wondering, and for what? I just chalked it up to other people sucking. The way they treated me isn’t a reflection of me, it speaks more to their own shortcomings. I still get mad at how they treated me sometimes, it’s not perfect. But it has made my life a whole lot happier when I let this go. It’s time for you, too.