Passkey is some sort of specific unique key to a device allowing to use a pin on a device instead of the password. But which won’t work on another device.
Now I don’t know if that key can be stolen or not, or if it’s really more secure or not, as people have really unsecure pins.
That suggestion up thread to read up on how webauthn/CTAP2/FIDO2 works?
It’s a good suggestion. I would take it.
I don’t think you know what an attack surface is.
I do. What part in particular worries you?