I do hope you will be making it clear that she will not be invited on any more holidays.
Tell her she will be punished when you get back home unless her attitude changes. A lot.
Don’t let her bad manners become the norm, if your DH doesn’t nip this in the bud, she will talk to both of you like she talks to her mum and that is not acceptable.
I do feel you pain op, I moved in with my now DH when his daughter was 12, as I said I would not move in once she hit those horrible teen years.sadly she was with us 100% as her mum had died a few years prior, we never did get on.
I’m sure there is something she wants or some place she’d like to visit, withhold until she apologises and bucks up her ideas and make it clear she will never holiday with you again. Also make sure she hears you tell her dad that you deserve a nicer holiday somewhere lovely asap for putting up with her disgusting and disrespectful behaviour.
I hope you and DH are not treating her, if you’re in a restaurant and she wants to order coke with her dinner, order her water and explain that she can act like a brat, but you can be an even bigger one. If she wants to spend another day at the beach, tell her you have no desire to spend a day at the beach so you’re all going off to the local museums, art gallery, photography exhibition, market, park or basically anywhere she will not want to go. When she kicks you ff, tell her it’s the same as the coke vs water scenario. Good girls get rewards, brats don’t. She’s well old enough to understand and behave.
Never take her away again.