I had the same issue with the LG Stylo 4; phone appeared to not be charging and would not power on. I remembered the trick of holding the power key on the right side and volume down on the left simultaneously, with charger plugged into phone. After about 20 seconds, it powered right up, showing a 100% charge. Performing the reset was not necessary, I allowed the phone to continue powering up once the LG logo appeared on screen. Once the power up completed, the phone ran as normal. Don’t perform the factory reset unless as a last resort.