Hi, when you say that your SOT (Screen on Time) has gone down, can you share the SOT after trying the below:
1. Charge the battery to 100% & use as per your normal usage pattern
2. When the battery strength reaches 10%, go to settings = Battery => Tap on the battery icon & share the graph
3. settings => Battery => Check the screen & share the same
You may also follow the below steps:
1 . Factory reset your phone after taking a full backup :
https://www.asus.com/support/FAQ/1006346/2 . Last option would be to visit the service center to have
a check. Locate here:
https://www.asus.com/in/support/Service-Center/India