Shade

Dark displays.
A working Mac.

Keep Computer Use running while every online physical display is dimmed together. Move your trackpad to return, then let Shade dim again when you step away.

Drag Shade to Applications. Turn it on from the menu bar. Choose a dim delay, record a shortcut, or enable Wake on touch. The Shade shortcut always restores every display.

Dimming doesn’t lock your Mac. Shade is a privacy band-aid, not security.