Like Batman and the Joker, then. Lol.
Sorry, I got excited and thought it was gonna be enemies-to-lovers.
Personally my story doesn't follow light-novel style tropes, but my story's "villainness", I suppose, starts off with a cheery, flirty and unserious demeanour, then quickly reveals a violent, possessive obsession with the protag, which looks like yandere, but the wiki I read states though that real yandere must be a sickness born from A's love for B—while her obsession is a result of a warped attachment style born from childhood trauma.
So I guess there is a distinction between a yandere-inspired character VS the fictional, archetypal yandere character.
Either way I fw the dynamic heavy tho as a writer and reader. So much you can do with these character bases and their relationship. Either redeem and evolve, contaminate and spiral, inspire or destroy, or all of the above? Your ideas sound really interesting, as well.