Try the below:
Make sure you are on latest software version which is .78, you can check by
Go to setting => About => Software information
Factory reset your phone once
Share a video if possible capturing the issue.
For quick solution:
Kindly visit the nearest service center:
Due to the lockdown, service centers may not be functional. Kindly call the service center before you visit one.
https://www.asus.com/in/support/service-center/india