Chosen Solution
I got a new phone it didn’t come directly from Apple but it is brand new. I had problems with it the first night and found out it was a software bug but it got fixed. It’s been a few days later and now my phone won’t stay on unless it’s charging. It’ll completely shut off and when I try to reboot the logo will show and shut off again. My phone is at 100% but it has to be charging to work. Is it the battery that’s the issue?
Apple has been building iPhone 6 Plus for quite some time now so it’s hard to understand how this device can be “new”. Even if it is fresh out of the box, there is a high likelihood that the battery is dead or very weak. That would be the first thing I try if I were to repair it. Because you bought it new, you may have some recourse with the vendor so you’ll want to explore that as well.