Passkeys can be transferrable and syncable ( see keepassx, bitwarden, and relatives). But ideally, eventually, you never sync them because every time you log into a service with a new device, that device gets its own passkey. No need to sync them and you can revoke a devices access if it is lost or stolen without effecting any other device. They are closer to client certs than passwords in that respect.
Passkeys can be transferrable and syncable ( see keepassx, bitwarden, and relatives). But ideally, eventually, you never sync them because every time you log into a service with a new device, that device gets its own passkey. No need to sync them and you can revoke a devices access if it is lost or stolen without effecting any other device. They are closer to client certs than passwords in that respect.