what I would with her is that she have mommy issues, that she is not all that bad but her mother is true evil piece of shit and her father a weakling cuck.
the mother is just mentally and emotionally abusive torwards both her and her husband.
ergo she is extremely insecure and is afraid of showing her good side to others in fear that they won't like her as a person and hide it in the form of being a total unlikable bitch mask.
what would be a good start of her to change and become a better person would be by ironically getting help.
I think marco or janna accidentally sneak-peaking on a chat between her and her abusive mother would be a good start.
it'll make them realize that maybe she is in great trouble and that she NEEDS help even if she doesn't accept it.