OP I understand where you are coming from, but you must not think it is too late to feel happy and content (with or without her support)
Perhaps the hardest journey throughout my life was coming to terms with what you describe, having been raised to idolise my mother I have always thought it was me that was the problem, until I had children of my own and the scales fell from my eyes well and truly.
Then the pain of the realisation that she was highly manipulative, only interested in herself and choosing not to help me during a life threatening illness, which I won't go into, it was just awful at the time. The more the fog lifted so it exposed such a toxic underbelly to my family, and her place within it, I found it unbearable for a while.
The grieving process is really really hard, I won't lie. It was horrendous letting go of my hopes and dreams of what I thought she was versus the cold hard reality, but finally I did make my peace with it, and you will too.
It is a process that you need to work through. You will eventually feel much better than you do now.
I now accept her for what she is, we have a low contact civil relationship that is limited and capped so they can't hurt me anymore. I don't ask them for anything ever, I never expect anything from them. Even in the worst emergency I will never call my mother - because I know she won't help and will drain me by prioritising her feelings.
I no longer for the ache of the loss. I no longer cry because I need a motherly figure. I have established a tight network instead that I turn to if I need to, I have become fiercely independent, and I deal with my own issues. I don't look to them for anything, and so it is left in a good enough place, with very little investment on either side. I am comfortable with this. I am happy with my own children, and raising them and spending time with my own little family has been a life saver for me. Be grateful for everything you have 