Is your problem fixed?, I was same problem with Galaxy S7 Edge.
All suggested already tried, but still got same problem. Each time for the black screen, with [vol -] and [power button] pressed the program restart.
After experiencing several times with the problem, I believe this is a problem wake up failure after the black screen.
It is possible that the original program to wake up the problem screen have bug.
Lastly I tried to download the theme provided by samsung and untill now the problem solved.
I have the same problem, it has been 2 days and I have tried everything, I even took it to a repair shop and they told me it is the motherboard. The battery won't die, I don't know what else to do, please help...
I fixed mine by letting the battery go flat. Got it started in recovery and factory reset it. It even installed the system update that caused the problem in the first place.