Unable to sign into Yahoo using a passkey

Security Key = Passkey, though in this case Yahoo may only allow you to use it for 2FA, rather than an authenticator app, instead of completely handling login. I seem to remember, however, being able to sign in with a passkey alone, once I removed my authenticator app 2FA.

Not all sites have upgraded to allow Security Keys/Passkeys for complete 1 step login. However, even on those you can still create a security key, which 1Password will store as a Passkey, and eliminate having to fill an auth key. Presumably, if they aren't knuckle heads about it, once a site enables 1 step passkey login, the passkey you setup via their security key option will 'just work'.