For a few years now, my DP-HDMI adapter has failed to wake up one of my 3 monitors.
While the other two monitors are plugged in without adapters, regardless of which monitor the adapter is used on, when the computer is brought from a screen-off state, the monitor with the adapter never powers on. It remains in standby.
If you unplug the cable entirely, and plug it back in; The monitor comes on.
If you disable and re-enable the graphics driver in Windows; the monitor comes on.
When you restart the computer, or do a cold boot; the monitor comes on.
It is only when the monitors have been turned off automatically from inactivity, and then you go to use it again does the monitor not get the wake signal from the adapter. The easiest solution is power cycling the monitor but it’s gotten to the point where the power button is starting to fail from the daily having to turn it on and off just to make it work.