This is brilliant, it's like you're writing about my mother and I. My mum also left when I was 14 (she just ran off, disappeared one day), she came back after 6 months but the damage was done. In many ways, I would have been better off living with my dad, but that was not an option. My teen years were very depressing living in an extremely chaotic home. She has suffered from mental illness as long as I can remember and has never been brave or strong enough to seek help. It's sad that she has wasted her own potential and her relationships with her children, I feel pity for her now, my anger is gone.
It's taken me a long time to accept the mother-shaped hole in my psyche, I'm learning to be my own mother too. I always longed for the time when I felt she loved me, when I was very young at around 4 years old, but I think that nostalgia was largely fabricated to protect myself, as you described.
Great article, thank you!
Edit: Just to say, I had 6 months of therapy in 2019, which started my healing.