I guess what I’m trying to say is that the shut down can take some time and therefore startup will not occur until the phone has fully shut down, no matter how long you hold the power button. As soon as it initiates a shutdown, it will disconnect from anything and show a black screen, but with my 11, I know it’s still shutting down because I can still see the faint backlight (like I said in my previous post) but your phone has no indication that it’s still shutting down as there is no backlight. I believe that you are having issues with powering on your device because when you are pressing the power button to turn on, your phone is still shutting down.