This is probably the infamous "dead strip." or Apples response to planned obsolence. I havent found any real solutions that worked for me. Some have reported having success with rolling back to an older iOS version and custom editting their settings tab to include the touch sensitivity option. This sorta worked for me...but it only seemed to relocate the dead strip to another section of the screen. But you probsbly cant even try that if you cant unlock your phone. You most likely have no other option other than replacing the entire Front panel even though the problem is only thr digitizer.
You said you tried mayer's advice in the other thread suggesting to check the pins on the power adapter for being loose? Have you tried another power supply? I know when I brought mine into the Apple store they used theirs so that threw me off. I still don't understand how my issue appeared to be power related when, like you, I was still able to get a solid green light and charge my battery. When I started to test each piece connected to the logic board I started getting funny responses from the adapter. It would be feint green at times, when I'd trip the power pads, it would blink orange, sometimes it was solid green. I would disconnect the whole I/O board and then reconnect it to make sure all the connections are good. I feel like mine might have been loose somewhere. Hold the adapter to the port physically to make sure its connecting properly. It seems like its getting power initially but theres a weak connection somewhere.