I really feel your pain. I am in a very difficult relationship with my only daughter. Having raised her more or less singlehandedly since I left her father when she was two, we had a very close relationship until she married and had a baby.
She has always been rather reactionary, however (like her dad). She now devotes all her energy to being a mum and wife (which I get) but to the complete exclusion of me and her only four other relatives on my side of the family. She's putting her in-law family on some kind of pedestal, has little respect for her elders -especially if we dare to have a different viewpoint - and I'm probably guilty of stepping on eggshells. I often wonder whether things might be different if she had siblings to 'compete' with. It's like she has had some kind of personality change.
It's so easy to dwell upon it and ask ourselves what we have 'done wrong', though I do think that society and social media doesn't help relationships these days.
The more time goes on, the easier it gets to become less emotional about it. I know I'm not the only person in her life that she has issues with, so I focus upon that. Does your daughter struggle in her relationships with others, too?
I really wish you peace and happiness. Focus upon everything that is good in your life and know that you have done the very best fort your daughter.