Hi there, kindly follow the below steps:
Check with other headphones/ earphones and see if the issue persists
check the headphones on another device and see if the issue is with the headphone.
Clear system cache.
Try the same under safe mode:
Hold the power button for 5 seconds => When the screen flashes with option => Press & hold power option => You will get an option to restart in safe mode
5. If still you face the issue factory reset your phone after taking a full backup :
https://www.asus.com/support/FAQ/1006346/ 6. Last option would be to visit the service center to have a check. Locate here:
https://www.asus.com/in/support/Service-Center/India