Struggling with 12 yo behaviour I feel it's become so intense and her unhappiness seems hight

[Whattodo12e]

What do we do with dd she seems so unhappy with us, she's constantly rude and combative even if she wants us to help her.
She's not let us cuddle her for years now.
She's intensely self conscious out and about and has gone weird over clothes she wants baggy plain stuff but won't have anything remotely nice or patterned. That's absolutely fine I don't mind what she wears but it makes trying to buy clothes hard even though she's choosing.

She won't come and eat downstairs, she is hard work she had a day out yesterday and we said we understand it's going to be a bit boring but she makes us suffer all day, this wasn't right she's in a hell hole she's being forced to do x y and z etc.
My patience is running really thin I dragged myself out of bed last night just as I was about to fall asleep to help her find some clothing I'd washed I could hear her crying and I was worried I hadn't put them where I'd said. So I went into her room and they were exactly where I'd said and I said it nicely oh here they are and she was absolutely vicious.

Has this been going on for a while or new behaviours?
Has she had any difficulties around eating before? Refusing food or disliking smells and the sound of others eating? Is she eating food upstairs or hiding or disposing it somewhere? What does she eat at school?

You say “ gone weird” over clothing. This could be her maturing and wanting to assert some independence. Alongside the not eating with you though, this could be body image problems. Maybe she isn’t happy with the way that her body is developing.

I’d get some puberty books for her and try to be calm and open to any questions.
Hopefully it is puberty and teenage type behaviour.
Try to gently explore if anyone has been making comments IRL or online?

Use some planned ignoring when you can and praise as much as possible. Try to be consistent with any rules and strategies.
Offer choices if you can to give her some control e.g. where to go for a day out or to stay with relatives or friends if she doesn’t want to go.
I wouldn’t try tackling everything at once but focus on the most concerning difficulty first.