from 7 hours on screen to 5.5 hours on screen without playing game and heavy tasks
Lower the screen brightness?
Reboot it and then leave it to sort itself out, i have always found that when this kind of thing happens it is only a matter of time before the OS gets back to grips with things.
Things like this are almost always a rogue app that hasn't shut down properly and is stuck in some sort of loop. Most get reset with a reboot
It looks like you're new here. If you want to get involved, click one of these buttons!