Chosen Solution
So basically when I started noticing that my phone has started to turn off by itself while i’m in the middle of listening to my music. I’ve tried factory reset, and sadly the problem has came back up. The only way I can turn my phone is when it’s plugged into a charger and I hold onto the volume down and the power button. I want to change the battery but I feel like there’s another choice that can help.
Battery sounds faulty, but you should get it replaced or fixed under warranty if possible. Backup data on your device if needed first before going for warranty.