@EricaZelic Store passkeys on devices that users have with them. Secure those devices with local-only secure biometric storage. Require biometric match to use passkey.
If you have any doubts: The people who say Earth is a chubby spheroid with equatorial radius of 6378.137 km rotating every 23 hrs 56 minutes can predict decades in advance where and when to go to see an eclipse. People who say Earth is flat can’t say when it gets dark at night.