A courageous post for sure, I commend you for sharing. I don't know that I have any advice (and you may not even be seeking any advice anyway, lol)...
But I will share this: I may not totally understand where you are coming from, but I'm struggling hard right now with liking the person my own son is becoming. I'm sure this is considered horrible (demon-mother, I know) but the influence of transactional love and humiliation 'lessons' I received from his father for years are now showing up in my son's behavior and it is repulsive to me.
I'm not going to write my child off but I'm also not going to allow anyone, ever again, to co-opt my being or allow them to render my Self invisible. That may mean sharply limiting my time with my son (which I rail against because, you know, demon-mother true-colors appearances are not pretty in the eyes of our culture).
Yes, our circumstances are different, but I also don't miss my son when he's at his dad's every other week... I don't care to talk to him when he's at his dad's, either, and I will happily acquiesce if he wants to stay longer.
If I had any advice at all (and if you are of the mindset that you would like to put in some work to grow for your own sake), it would be this- seek out growth in the form of emotional intelligence. Personally, I don't see the same value in therapy that many others do (which I'm sure stems from my limited- and therefore biased- experiences). I have been seeking and studying what we call 'emotional intelligence' as a focal point for the last few years (lots of interest in this topic, but it became a necessity in the latter years of my marriage) and realized that because I didn't know what I didn't know, haha, I had no reference point from which to draw- and therefore, didn't know that I was missing something!
I didn't do this by the usual route of self-help books or therapy or hitching to the happiness wagon... my sources are many and varied. This has been a painful journey as well as the most rewarding I've ever traveled. For me (as it is with many), it was either start moving along that road and seek some peace and healing or disappear. Seeking that growth may not be in your wheelhouse at this moment- or ever. But I'll tell you what, even though it is in mine, I don't know that I could've been induced to get moving if I hadn't been staring my own dissolution in the face! (we humans are funny like that).
It may very well be that you are good with the situation as it is, and aren't looking for things to change. But learning and modeling how to navigate through the emotional muck of life is part of parenting, IMO, so I'd say let your son see that- that you are growing and learning for your own self. Consider it part of your parenting obligation to your offspring and arm your son with the tools to grow and learn as well. It may not change your relationship with your son, but it will be a boon for him in his life- and isn't that what we are after? To want for our children to lead happy and successful lives?