If you have recently installed the 17.0823.2007.58 or the newest 17.0823.2008.70 and still have the black crush issue, then you have to try this:
The app is called screen balance and you can find it in google play. Just install it, give all permissions, including run over other apps, and set the bars like this:
first bar: fluorescent
second bar: 50%
third bar: 100%
fourth bar: 0%
After that just press the switch in the top part and DON'T CLOSE THE APP. The black crush should be less noticeable in relatively lower brightness. If it didn't work for you in 50% on second bar then try 55%, 60%, 65%, 70% or 75% until you feel comfortable. higher than 75% will result in black looking like in LCD screens.
As you can see the black crush issue in this phone is a software bug, not hardware. We just have to wait for the devs to do something.
And dear devs, this is fixable. Please take care of your community. Many people have spent their well earned money on your products and an issue from this magnitude is unacceptable. I understand that this issue is present in almost every OLED panel, but please do you best to reduce it as much as you can.
And also notice, this is a temporary fix, which means not permanent. Don't get mad at me