I think you mean that passkeys potentially skip the something you know. The something you have is the private key for the passkey (however it's stored, in hardware or in software, etc). Unlocking access to that private key is done on the local device such as through a PIN/password or biometrics and gives you the second factor of something you know or something you are. If you have your password manager vault set to automatically unlock on your device for example, then that skips the something you know part.