Gosh you're really hurting OP. I wonder why you're so hard on yourself? Were your grandparents a bit too hard or "honest" with you?
... there must be something wrong with me. Because I failed to trigger unconditional love in my mother that would walk through fire rather than be separated.
I would like you to have a look at this Google Image search on babies.
https://www.google.com/search?rlz=1C1CHZN_enIE949IE949&sxsrf=AB5stBi0AK4C1gIJDL9ffefzr_a25gAqDA:1688509607262&q=babies&tbm=isch&sa=X&ved=2ahUKEwiCtNy6jPb_AhVVmFwKHTZ8ADoQ0pQJegQIChAB&biw=1396&bih=656&dpr=1.38
Logically, do you think there is something in any of these babies that "fails to trigger unconditional love in their mothers"? No, it doesn't work that way. The issue lies with your mother, for whatever reasons she let you down.
I was adopted. My birth mother went on to have more children, my half siblings. It's a complicated story but whereas I know she was completely self-involved and was not able to consider my needs or feelings when she found me after many years, I do not understand where this came from; I do know I can't change it. She had a dysfunctional relationship with my half siblings so that's a dead end.
My birth mother is a covert narcissist who married an alcoholic. So, to put it mildly, my childhood was utterly chaotic. In her case I know things happened in her youth which damaged her severely, unfortunately it resulted in me being abused horrifically. Until recently I had an underlying belief that everyone in the world had more value than me. Thinking about it, that is a crazy belief to have. I'm about 2 years in therapy and have a way to go yet, but I am starting to value myself for the first time in my life.
So what I'm trying to say to you OP, is to be a bit kinder to yourself. You have been seriously affected by things beyond your control. If you're out and about and you see children, perhaps consider how could they be in charge of their lives, how could they not be affected by their parent's issues? They are only young, their parents' responsibility is to protect them, love and nurture them and hopefully try not to bring them up consumed with guilt for merely existing.
Your mother was a very damaged person. Sadly that has caused you untold grief. I hope you continue with your therapy and can find the real you under all that trauma. You seem very defensive about opening up and I wonder why that is (not asking you to disclose anything here). I have been told I am far too hard on myself, and for the last while I have tried to look at myself as someone who had to battle through so much at far too young an age, and to try to treat myself with kindness. It is slow going but rewarding.
Sorry for the long post, I hope you find some of my musings helpful.