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.
I don’t think you understand what an attack surface is.
Lol. I guess you learned a word from the CEH you flunked.
Edit: but yes, passkeys greatly reduce the attack surface compared to a password.
And when using a properly hardened device like a yubikey, you can actually minimize your attack surface to as low as it’s ever going to be in a web context.