Any Male-Lead Crossover, Roleplay, Secret Identity, or Cosplay Transmigration Stories?

More Bungou Stray Dogs and Jujutsu Kaisen, please. The characters being cosplayed or impersonated can be anyone, as long as it's one of those series. Secret identities, like playing different characters in another world, are fine too. No harem stories! Nothing with too many major flaws! Ideally, the protagonist isn't a girl!