Thank you for your asking. Can you still back up your data via USB cable? Please try the following steps to access recovery mode for the Factory Reset:
0. Try to back up your data with USB cable
1. Power off the phone, then keep pressing "volume down key"
2. Press "power key" and stop press " power key" once you feel the vibration. Still keep pressing "volume down key".
3. Stop press "volume down key" once you enter [Android Recovery] Screen
4. Choose "Wipe data/factory reset">"Yes"
5. "Reboot system now"
#Hardware Reset Guidehttps://www.asus.com/support/FAQ/1006346/
Please note that once the steps are completed, all data, apps, settings and personal information will be deleted.
If the situation remains the same, according to what you described, please contact ASUS repair center in the country of your residence: https://www.asus.com/support/Service-Center-All-Countries/
If it is impossible to access the service center during Covid-19 period, please try Call us: https://www.asus.com/support/CallUs