LG G5 Charges but won't turn on

if the battery runs zero, upon plugging, battery shows 0% on screen but indicator on top of the phone blinks then turns off. This is the only time the screen turns on to show 0% and charging, when the screen sleeps, the battery continues to charge while plugged but won’t turn on.

after an hour of charging, the phone won’t turn on, the unit just vibrates once after pressing power button, and nothing else can be done. I have to remove battery to try again but the same thing happens after pressing power button.

tried to enter bootloader mode or download mode with vol down + power button, but nothing happens to the phone. screen remains blank. it doesn’t vibrate as well.

any help to pinpoint the problem is appreciated. I have tried changing with a new charging module and new battery but phone remains the same.