OP, she's dictating to the house and that is never good.
At 19 she needs to learn some manners.
I would not accept the rudeness about your food.
Cease providing food for her.
Cease any laundry.
Insist she makes a financial contribution.
Lock the door at night and assume she's not coming home.
If she wants to stay with the boyfriend, then fine.
But I would not allow her to dictate to the house and cause upset.
Coming and going is very normal for 19 years, but so is courtesy.
If one of children was rude enough fo tell me my food was rubbish, they wouldn't forget it for a long time.
She's very rude and that's not acceptable.
The sooner she moves out the better.
I wouldn't hesitate in telling her that.
Families have to work as a team with politeness towards each, otherwise it's awful for everyone.
You sound like you have a huge amount on your plate. I would read her the riot act and if she doesn't improve maybe give her the experience of being locked out.
It's a very tough world out there and she sounds like she could do with a dose of reality.
I bet her boyfriend's family are also hoping she jogs on too.
I know lots of 19 year olds and while they definitely can be selfish at times, they buck up promptly when it is pointed out.
Wishing you well OP