I went NC with my sister almost 2 years ago. TBH I would have done that many years before but she never got the polite message that I really didn't want to see her.
I have my reasons for going NC but overall I always found that her presence really put me on edge and we were always fighting. We just couldn't get along. That to me in itself was enough reason.
I've never had any proper attachment either, so ultimately I just didn't care. I'm on the spectrum, but was diagnosed in my late 30s (which I think has a role in this too).