Idk if it’s bipolar disorder since I don’t know much about it but I agree
Her “dark side” is basically a scapegoat for whenever she does something wrong.
It’s more comparable to Hollywood’s understanding (misunderstanding) of dissociative identity disorder, or the common interpretation of Jekyll and Hyde. The sort that people use in writing when they don’t want their characters to be held at fault for whatever their “evil second personality” does.
Sorry for hijacking your ask.