MekaninI did the update to Android 12 manualy also 3 weeks ago,3.6 GB file but yesterday i downgraded to Android 11,also manualy više Asus support site. And when i turned on the phone on Android 11,a systems software update notification poped up and was for last Android 12 build(OTA notification) Ande this time was 1.4 GB so half the size compared to the first manual update to Android 12. And i downloaded the update and im now on Android 12 again. Maybe this new OTA update will fix the battery. Maybe the big manual update was faulty in some way and was drainning the battery. This is my last hope.
I just update manually from A11 .82 firmware to A12, so far battery has a good improvement, right now my phone from 100% almost reach 2 days without charging, and now it still 13% of juice and the SoT 4 hours 45 minutes. I'm a casual user, social media (instagram, twitter), spending 40 minutes on youtube, spotify, mostly whatsapp and I say this battery life has a great improvement comparing the Android 11 where it will only last a day less.