This is a very common issue.

The way I solved it is:

Open the Terminal app.

Type the line below and hit enter.

caffeinate -d

You won’t get a reaction from the system, but the command will be active. Minimize the window.

It will keep the display from going to sleep for as long as the terminal window is open (which is why you minimize) and until you restart the computer (at which point, you’d have to enter it again. I use that command and manually turn the screen off. I don’t think it completely solved the issue, but it greatly reduced the number of times I had incidents where the display wouldn’t wake up. I rarely have them now. I had tried everything else and nothing seemed to work, so it may be just the command or a combination of the command and turning off any setting that would allow the display or computer to go into any kind of sleep, nap, or power save mode.