One of the most fun character concepts that I've had that I've never been able to fit into anything is The Most Appropriate Socialite Lady. Nobody dislikes her, but she is, indeed, very Appropriate, always seeming to do everything precisely to social etiquette, even according to social rules that nobody else knew were a thing. If there is a protocol to how to behave or respond in any given situation, no matter how obscure or how long ago it was that this was written down in some Refined Society Etiquette Book, she'll know it. So she is a bit old-fashioned sometimes, but not in a regressive way.
Every time there's a situation where nobody actually knows what the right way to respond would be, they quietly glance at her, because either she knows exactly how to handle this, or if the situation truly is without precedent, her educated guess of what should be done must be the right one. Someone might even write it down for a future etiquette book, of how This Most Polite Well-Mannered Lady responded to this awkward situation.
She doesn't judge people, and is never rude about people breaking Good Manner Rules on purpose (as pointing out someone doing so would be impolite), but the way she seems genuinely surprised and confused whenever someone breaks the protocol that nobody else might even been aware of makes people feel self-conscious or awkward sometimes. And she politely pretends to not notice that. She is very kind, very sweet, but also extremely Appropriate.
So even if this isn't a Victorian style gentlemanly "fine ladies are fragile and must be sheltered from the world"-style society by default, people still feel the need to behave well and be on their best formal behaviour around her, not out of fear of judgement but because she genuinely is that way and nobody wants to upset her. And if someone who doesn't give a shit about protocols upsets her on purpose by deliberately doing something that's fucking rude, they'll be discreetly moved to a different location before getting the shit beat out of them because fuck you for upsetting her.
The thing is, she's actually just autistic as hell. She originally started reading up on social etiquette as a way of masking, but it became a special interest for her, and she isn't just thrilled to teach you how to properly fold a napkin to help you better fit in to the Refined Society, but because she fucking loves infodumping. She's not trying to set herself apart, gatekeep, judge others or show off how she's better than you (like many others of her background would), she just genuinely enjoys having explicitly and clearly written rules and instructions on how to behave in society.
Also the tactful and graceful way in which she doesn't pay notice to veiled insults, or people accidentally saying something insulting to her, isn't always an act. A lot of the time she genuinely just does not notice.
