I would say to keep writing, you're processing stuff. Eventually, you'll get to what you really want and need to say. If you just let it flow for now without self-editing, it could be very revealing to you. For now, it's not about who you're writing to, but about you as you write.
My experience was that I realized my parents are never going to hear me unless they go looking for it, and even then they still might not, but I posted my goodbye letter as a thread. It brought a lot of peace. Since then, it occasionally comes up to write to them because of certain wishes like not wanting an obituary, and I could force that, but I come back to remembering how irrational, unreasonable, and controlling they are, and I remind myself that maintaining the no contact that's been in place for years is still the best option. Forcing what I want brings me down to their level, I would have to lie and manipulate. I realize that it's a relief to just be done with their stuff. After all these years, I'm still coming down from the abuse, control and utter craziness from someone who placed such a high value on being "normal."
