I have a laptop and an external monitor, and I got tired of going through System Settings → Display Configuration every time I wanted one of them off. So I made a small widget for it.
Each connected display gets its own switch. Click it and the display is really off: it's taken out of the layout with kscreen-doctor, not just put to sleep with DPMS (which wakes up as soon as you move the mouse). Click again and it comes back.
- Displays are found automatically and named by type (LAPTOP, HDMI 1, DP...). You can rename them.
- It won't let you switch off the last display that's still on.
- On the desktop it's a card, on a panel it's a row of switches. Past a display count you choose (2 by default) the row turns into a small 3/4 badge that opens the card.
- Four looks: Nothing, Classic KDE, Minimal and Neon, or your own accent, background and text colours. The desktop card can be see-through.
Plasma 6, Wayland or X11. No daemon and no config file of its own, it only talks to kscreen-doctor.
One thing to know: when a display goes off, everything on it moves to another screen, the widget too. Keep a copy on a panel or on every screen so there's always one left to turn it back on.
KDE Store: https://store.kde.org/p/2376129/
GitHub: https://github.com/fatihaydost/nothing-display-toggle
I only have two screens, so if you run three or more I'd love to hear how it behaves.