I have done inner child healing. I started with this book called “Carefrontation” https://www.amazon.ca/Carefrontation-Breaking-Free-Childhood-Trauma/dp/194287281X
For me, it wasn’t scary. The first part of me I found was 3-year-old me through doing the dominant/non-dominant hand writing. When I found her, she really wanted to go swimming. I had forgotten how much I loved the water when I was little and I took her swimming. It was the first step on my healing journey.
That's not rambling at all. I completely understand where you are coming from. Being neglected creates its own trauma which must be worked through, not unlike emotional and sexual abuse. Children need to know that they are safe, and they feel safe when they can share an emotional connection with people who they feel will protect them. For a child, care and attention from a calm adult equates to safety. When a child grows up with one parent, they aren't necessarily damaged goods as long as the other parent can love and care for the child. But if no one shows interest in the child, their heart withers, and they feel as though their life has no inherent worth. This I believe is why poor coping behavior begins around the teenage years.
All that being said, a parent cannot be taught how to care for a child any more than someone can be taught to love someone they have no interest in. In both cases the person must be inspired and their heart must be activated to seek.
One thing I think is important - who a child's parents are or how they behaved does not determine the child's future. In all cases, it is our action from this moment and on into the future that determines what kind of person we will become.
I'll mention a book that I think is essential for anyone dealing with childhood trauma. Carefrontation by Dr. Arlene Drake. All trauma can be cured when properly identified and addressed. https://www.amazon.com/Carefrontation-Breaking-Free-Childhood-Trauma/dp/194287281X