Wyze support indicates in the support article Can I still enter my home if WiFi goes offline? – Wyzestrong text that you can still unlock the lock if the internet is down and I have not be successful in see how that is possible. How do you tell the lock to unlock since the app will not even show the devices unless it has an internet connection. So without being able to get to the lock page to tell it to unlock how would that be possible. Keep in mind you may not have the auto unlock feature enabled since that is another feature and is not required for this, besides that would require you to leave the geofence and come back in again and have location services turned on and that may not be your desired settings.
The article says to simply connect the lock through bluetooth and unlock it,