You might speed this up by unplugging the monitor, then holding down the monitor's power button for a few seconds to discharge its capacitors, then immediately plugging back in and powering-on. The only reason I can see to wait 5 minutes is so the capacitors will naturally discharge, but holding down the power button while the monitor is unplugged should immediately discharge them.

This is true only for some designs. It's possible you could have a power island that doesn't get discharged and also has no connection to any buttons when the board is nominally off, and that the things in that power island refuse to reset properly.

There's a whole area of electronics design related to this (unfortunately).

Yes, that's a good hint. Most monitor power bricks have very large capacitors, especially when they also charge the laptop through the Thunderbolt connection.

That's also the point of the LEDs you see on power bricks. After unplugging, the LED uses up the capacitor current to discharge them faster and also serves as a visual indicator to know when it's safe to plug back the cable.

I have some dells (U2414H) that can get into a really bad state. Sometimes unplugging power is not enough. You have to remove all potential power inputs including display input cables (or shut those devices down too) to get a proper reset.

Funny, i have the exact same display and I’ve had it randomly not work multiple times.

Only unplugging everything seemed to work.

Happened maybe 5 times in the many years ive owned it

Does pressing power while it’s unplugged expedite the process by attempting to draw power and emptying any capacitors in the process?

My Samsung G7 monitor has this issue where DDC commands will occasionally lock it up to a black screen. I don't use Lunar as I'm on Windows (I use NirSoft's ControlMyMonitor).

On this monitor I can just unplug and plug the monitor back in and it immediately works again, but its an annoying enough issue and it happens frequently enough that I just stopped using DDC control for it altogether.

So if I have my cell phone (Galaxy S21) near my headphones USB cable, and there is activity on the mobile phone radio (I can hear the mobile phone 'radio' in my headphones), sometimes my monitors will black out. This has happened to a few other users at my office as well. Move the mobile phone a meter away from any cables and problem goes away.

I’ve run into this on the older ASUS model PB278Q. It’s otherwise a decent monitor, if a bit slow to turn on and switch sources by modern standards, but once in a while it’ll refuse to display anything and I’ll have to unplug it from power for a few seconds to “hard reset” it.

Leaving the power off for 5min also has the advantage of cooling the machine.