It doesn't matter how many different things have support for passkeys. Because they let websites do "attestation" of them, it won't be long until every major website is only allowing logins with passkeys blessed by Microsoft, Apple, or Google.
I'm not familiar with all this, but when I run the demo page (https://webauthn.lubu.ch/_test/client.html) on macOS 13.4.1 with Safari (Firefox doesn't work) I get "none" for the apple attestation.