Hi there, in order to help you kindly help us with the following details:
1. Kindly let us know the Charging time taken from 0 - 100%.
2. What's the charging time difference between the current & previous update.
3. Try another charger & let us know if there is any difference.
4. Use the ASUS charger on a different phone & let us know the difference.
5 . If the issue is with charger we suggest you to please visit the nearest ASUS service center for better assistance. Locate here :
https://www.asus.com/in/support/Service-Center/India