SOLVED. I believe it is a YA, it is based in a mental health hospital. I remember they could only socialise in the blue room. Read 2018-2020.

[Book]

I remember the cover being blue and with white shoes on the cover but I read it somewhere between 2018 - 2020. I read this as a physical copy from the library but can no longer find it. In my head I remember it being called “Blue” but can’t find it anywhere. It was set in modern times and I believe had LGBT aspects (but I could remember this wrong) I also remember the main character being a dancer. This book was published in English.

[Robert]

Possibly Suicide Notes, by Michael Thomas Ford?

"Fifteen-year-old Jeff wakes up on New Year’s Day to find himself in the hospital—specifically, in the psychiatric ward. Despite the bandages on his wrists, he’s positive this is all some huge mistake. Jeff is perfectly fine, perfectly normal; not like the other kids in the hospital with him. But over the course of the next forty-five days, Jeff begins to understand why he ended up here—and realizes he has more in common with the other kids than he thought."

[Book]

Seems interesting but no it’s not that one, the main character was female and the other characters were too.
Thank you though.

[Len]

Could it be something by Robert Cormier? I am thinking of The Bumblebee Flies Anyway but that has nothing to do with blueness or dancing.

[Riley]

Before We Were Blue? There's a lot of references to dancers/dance classes in it and the characters being designated as "blue" and privileged I think (and the main characters start as "grey")

[Book]

Ohh yes that’s the one, thank you so much.