I may be way off base here, but I had and survived 3 teenage daughters and this kind of stuff was typical for my girls at a certain age. One minute they would be saying they didn't eat breakfast so I was wasting my time cooking it for them and the next minute they were complaining I wasn't cooking them breakfast and they were "starving". Kids are kids are kids. Your situation is, of course, exacerbated by all the drama surrounding it, but you have to do your best to listen to what your D is saying to you and then validate it. Again, as many have pointed out, that doesn't mean taking blame for anything or admitting that you are doing anything wrong, but more just that you are actively listening to what she is saying. I can pretty much guarantee you that you will never "win" the girlfriend argument so your best bet there is to just listen to what d says and if she says you are shoving gf down her throat, tell her you are sorry she feels that way and ask what you can do to make it better. If she says she doesn't know your gf, ask her if she'd like to and how you might go about making that happen.
You have to go into adult active listening mode, not defensive the world is against me mode. Think about it like this.....you have been saying parental alienation all along and have been fighting to get others to agree with you and see it that way. If that is, in fact, what is going on, can you step outside of yourself for a minute and see how that puts your d in a bad situation if her mother is manipulating her?
She said she was never happy with you and you say you have tons of pics of y'all having a good time. That proves NOTHING. I have a ton of pics of me and my XH together, smiling, looking like we were having fun, just a month or so prior to our split. This is another time when you have to LISTEN to what she's saying and stop trying to prove that what she's saying is wrong. Ask her why she was unhappy, what made her unhappy, how you can help her find happiness. In short, make it all about her and helping her. You are the adult and you will have to compromise, but really digging in and listening to her and trying to see things from her perspective will go a long way to rebuilding your relationship.
Me 52, H53 Bomb drop 9/29/2014 Divorce from XH final 12/17/2014 Marriage #2 12/31/2019 5 adult (step)daughters (3 from XH's first marriage, 2 from current H's previous relationships) 6 grandkids