To understand your mother you need to understand narcissism. The NPD mother has no real deep connection, well with anyone really. The NPD mother does not, cannot love.
My mother was the same, in fact my mother told me she hated me.

IMO my mother was born 'wired differently' she has no empathy.

I remember no warmth, kindness or cuddles. I remember being at infant school on an 'open day' watching mums come in and greet their young children with a big smile, a hug, a kiss, delighting in them.
My mum wasnt like that, why? Why didn't my mum like me? Why wasnt my mum like all those other lovely mums?
I watched the door waiting, wanting, longing at 5 years old for MY mum to turn up. She didn't (as usual) Tears pricked, I held them back, didnt want to be cry baby, didnt want to make a fuss.
I felt lonely. So very lonesome.

I spent 45 years lost, wondering what I did so wrong that my own mother would despise me.
Then, I found out. Nothing was wrong with me. Nothing. Mother was a narcissist. A creature unable to feel love.

I do not belive narcissisum is cause by abuse (as is widely accepted) my mother was not abused as a child, nor was she a 'tortured soul' she was in fact disgustingly happy, she wrecked havoc on family around her however.

Knowing, understanding NPD has helped me. I now know I was the victim not her, that I am ALWAYS GOOD ENOUGH!
This website might be helpful;

The Narcissistic Parent - LIGHT'S HOUSE

There is more and more evidence to suggest NPD is an 60% inherited trait. Does knowing that make me forgive mother for her cruelies.

NO. Not at all. My mother was well aware of what she did.