You can still keep password + 2FA on GitHub and Google Suite (probably anything else that’s currently implementing them), it’s just a convenience/anti-phishing feature right now.
The passkey is synced between devices if it’s kept in a password manager, I haven’t looked at the mechanism that Apple uses to sync it/use it if you store it in the system keychain. I guess you could also have multiple passkeys configured for a few devices.
You can still keep password + 2FA on GitHub and Google Suite (probably anything else that’s currently implementing them), it’s just a convenience/anti-phishing feature right now.
The passkey is synced between devices if it’s kept in a password manager, I haven’t looked at the mechanism that Apple uses to sync it/use it if you store it in the system keychain. I guess you could also have multiple passkeys configured for a few devices.