[michaelt]

> If there isn't some form of automatic backup then I guarantee I will not have a sync when I need it the most.

As I understand things, passkeys come in a few different varieties.

You can buy a yubikey if you want the credential tied to one specific physical device. Figure out your own backup strategy, such as spare yubikeys or printed recovery codes or whatever.

Or you can use apple/google/microsoft if you want your passkeys backed up to your cloud account. This means passkeys are basically the "Log In With Google" button, but with extra steps.