You have my sympathy. Dd is now home from uni, and although we are lucky enough she has her own room we have ongoing drama about the amount of 'stuff' she has and doesn't want to part with. She has a large single wardrobe, a v large chest of drawers, 2 large drawers under her divan, a 2 x 2 kallax, and a small ottoman type thing.
She keeps telling me nothing fits, her clothes and art stuff and various other things. I keep reiterating that she has the space she has and to prioritise. There is no more space anywhere else in the house. And it wouldn't matter how much she had, she would fill it with stuff.
I think you need the same conversation with your dd. She gets the smallest room as a singe person. Everyone else is ssharing. That's how it is until they are financially independent enough to have their own place. They get a space in the family home and that's what they have.
Your ds's need to get used to sharing, but try for single beds rather than bunks if possible. There are some really good storage solutions under beds now, either cabin bed style with shelves and drawers, or lift up ones. Ds 11 needs to not fuck with ds 13 stuff. That needs to be a firm rule, with consequences if he breaks them. Ds 13 needs to understand that his brother is younger, and excited to share again and be a bit tolerant.
Id also ask dd that if she stays out, or is at work if ds13 can use her room for homework or chill time. Obviously there needs to be rules and respect. Or maybe he can go in your room for chill time, again with rules and respect in place.
Id also say the TV in their room is only to be on if they both want to watch something together. Rest of the time they use personal devices and headphones. Im with ds13 here. My ds who is also 11 watches the most amazing amount of crap on his and it would drive me insane.
Your dd also needs to remember she is an adult and needs to be contributing at home with a fair share of chores and paying board when she is able to. She also needs to get a job ASAP, even if it is not what she would ideally chose. She needs to be realistic about the current job market. Its not great.