Huge identity formation stage/transitional stage at that age, where they're adults but still have developing brains and are having to make sense of who they are when they're alone in the world - especially after all of the high excitement of uni/parties/freedom/new relationships and then the extreme pressure of studying/adult expectations/managing a house and dynamics.
To some degree, to be expected as she emotionally 'separates' her identity from you- her hometown- childhood.
However, the rudeness shouldn't be tolerated, she still needs to know how to behave as an adult and how to handle herself.
I remember staying home for uni, not moving away, and telling my parents they had 'trapped me' here. I made the decision of my own free will, to save money, and was incredibly lucky to have a safe, stable, loving home to study from! I cringe when I think back on that. Anyway, I'm still in my hometown, moved away for a few years for work but love my hometown despite the flaws now. Adult life brings perspective that the grass might be greener for a while, it's still just grass! I have a strong relationship with my parents and see them most days.
I would pull her up on rudeness and how it makes you feel, don't give in to unreasonable demands - she's an adult, she can get herself about if she's going to be rude, and give her space to figure stuff out and mature some more. Hopefully she will settle down and maybe you can have a few good days together over Xmas