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
Please follow below steps may improve battery backup:
1. Close apps that are not used (Bluetooth, WiFi, GPS, etc.)
2. Adjust sleep time and brightness (Settings > Display)
3. Boost memory when you see memory consumption is high with no app running,
4. check for background running applications, stop/disable unwanted apps, you can manage apps from auto-start manager.
5. Check the following article for more information: https://www.asus.com/in/support/article/604/
For performance issue try the below troubleshooting:
1. Check if there isn't any third party app which might have caused the device to slow down
2. Your device should have a few % of storage left as less free space on the device can cause a device to run slow
3. Ram management - there should always be adequate RAM available if the device needs to work flawlessly
4. Restart whenever you face this issue
5. Restart the device in safe mode – i. Power button hold for 2 seconds, ii. tap on the power off message which pops up on the screen, hold for few seconds it will give you an option to boot in safe mode.
6. If nothing work you can back up your phone & factory reset your device.