I have a very good friend who was in the exact same position.
A lovely mum who was far more of a 'carer' than me. She had been a sahm until divorce and then had a job that was flexible enough for her to carry on with the full time mummying (even though they were late teens by this point) .
It is her default mode . She was doing all the stuff I had stopped post primary school and getting cross about their lack of responsibility. ie making pack lunches, cleaning their rooms, doing their washing and putting it away. Not expecting any help around the house (no chores - just waited on hand and foot)
Then she met her partner . Child had gone to Uni so her waitress-mode had changed. Mum had got her own life ... then child came home for the summer and all hell broke out.
Massive tantrums that mum wasn't at beck and call. Just like OPs daughter, would demand shopping trips , lunches , Guilt mum into cancelling plans with partner - then cancel on her when a more fun offer came up with friends. This is just a snap shot. The child's behaviour was appalling. Basically accusing mum of putting her partner first and behaving like a 5 year old.
I encouraged her to sit her down and try to talk to her as an adult. It wasn't going to happen overnight as frankly mum had been such a wet blanket with the kids for years- that a lot was that she had made a Rod for her own back and will take a long time to undo..
The ONE thing she did manage to put implement was a diary. She gave her child her diary for the week with her time blocked out. Told child to put in times and activities they wanted to do together. BUT explained clearly that if they cancelled then they may not be able to rebook her as her 'blocked time' was non-negotiable and child had advanced warning.
It isn't perfect but the beginning of a boundary and made for an easier time and relieved my friends guilt .
Just to add. Friend also tried the 'child is having a hard time, emotionally fragile etc' - She isn't. She's a robust 21 year old . Actually a lovely young woman when not manipulating her mother.. she has just been patented by both her parents with indulgence and no boundaries. So this is the result.