how to test screens and DRM without x11 or wayland

I'm trying to debug why I can't have all my screens on at the same time. In order to zero in on the problem, I am hoping to find an easy way to control my screens without involving X11 or wayland - just a program that turns a screen red for example that I can use in tty mode. Is this possible? Another thing that might help is if there is a way to configure which screens do and don't show the terminal. You know how usually all the screens show the terminal, but if you plug in the screen while X11 is running, and don't activate it, something it doesn't show the terminal in TTY mode? There must be a way to turn screens on and off in TTY mode right? I guess I am just looking for any way to display something on a monitor or turn it on and off without X11 running. I'd even be happy to ssh into my machine, and control the screens that way if there is a way to turn off the console completely.