SOT has been gradually declining

At first I used to get 8hrs then it dropped to 7.5 to 7 to 6.5 and now I only get around 6hrs from 100% to 15%.

*Mostly on Wifi the whole day *FHD+ *120hz *Apps are in deep sleep *Wiping system cache after updates *Switched to Brave from Chrome *Not too heavy on social media apps

Any way to improve this?