There was one guy here I forget who that performed these coding gymnastics to get secp256k1 quasi-working for passkeys/webauthn via the PRF extension and a bitwarden software vault and a bunch of other stuff, and the result I'm guessing was something impressive but that can't really function in the real world given that webauthn mandates that it's up to users to choose how they want to store passkeys, not websites, and users will just choose keychain or whatever they see first.