I have the exact same issue as this thread describes: https://rog-forum.asus.com/t5/gaming-monitors/asus-pg27aqdp-perma-black-screen-after-powering-off-on...
This issue started few months ago.
After powering off my monitor it won't display anything after being turned on. What fixes the issue is unpluging and puling the disport port cable from my gpu. Also restarting the pc also works if the pc powers on while the monitor is on.
