I ran a 3x3 grid configuration for a long time as well -- until I finally realized I needed more than that and upgraded to a 5x3 grid! π οΈ
I use the center desktop for a maximized browser window and the most important stuff is usually in a plus shape immediately adjacent to that with less important things further away.

If you're on linux with X11, you can run
xset dpms force offto turn the monitor off. Either call manually in a terminal or add to scripts where needed. (I assume wayland probably has something similar too, but I don't know what it is specifically.)Most desktop environments already have a GUI-based way of setting an idle time-out if that's what you're looking for; this is a way to call it immediately.