Suggest me a book with a female protagonist who is fun, funny, witty, and charming but also secretly crazy and insane

Please suggest novels featuring female protagonists who are really lively, charismatic, talkative, and bubbly on the outside, but on the inside, they are mad/crazy/psychotic. Now, when I meant crazy, I didn't just mean loner/outsider/anti hero/ "I'm not like other girls" archetype protagonists. I meant someone who is a complete nut job, mentally ill, and utterly out of her mind. Also, she doesn't have to be a serial killer to be shown as psychotic, just someone who has a very strange and crazy worldview.

I did find some insane female protagonists, but they are all very serious, depressing, or very introverted. What I wanted to read was someone who pretends to be normal by being all cheerful and hilarious but is actually crazy inside. In short, I don't want the protagonist to be depressing but the opposite. Also, I would prefer it if there's no romance in the story or at least romance was featured only as a small subplot. I don't really like novels that featured male lead povs, and their romance interfered with the protagonist's madness.

"Orion you came and you took all my marbles" would kinda fit as an example featuring a fun and insane female protagonist, I think. Someone also recommended me "The Library at Mount Char" but I haven't read it yet. So can you recommend me novels like that? I know my requirements are a bit specific, so any recommendations at all will be greatly appreciated. Thank you for your time.