Transitioning from VLC to NC. Is final communication "required"?

Hi, all. I would love to hear your thoughts about the transition to NC after a period of VLC. Did you make final contact at that point to let them know? Or just block their numbers and move on? something else?

I struggle with the idea that we "owe" them an explanation or heads up when we go NC. In my case, I've spent 45+ years trying to explain myself, and I have only been dismissed, minimized, or told that I'm being melodramatic. So why bother trying again? After 2 years of VLC, I got a text from my father and sister at Xmas that sent me over the edge, and triggered a mental health crisis that took me several days to recover from. Clearly, I can't handle even planned, expected texts from them (I assumed they might reach out for Xmas, and had braced myself for that), so an unexpected message at a random time in the future could be dangerous to me, frankly. So I blocked their numbers on my phone. Any emails from them are automatically forwarded to my husband, at my request. Today, my therapist said she's proud that I took those steps. So that was validating. But I can't shake the idea that I owe them some final communication... and yet history has taught me that it's not worth my time or energy to try to explain. I'm stuck. I would love to hear your thoughts on that.

(For context, my father and sister know I've struggled with mental health issues all my life, but they are blissfully unaware that it was a dysfunctional household with emotional neglect and abuse. They would be shocked to know that I - and several therapists - view them as abusive. Their narrative is that I need God and family. They are not capable of introspection or empathy. My father is in his early 80s, so I hope he dies soon. But he's annoyingly healthy.)