It would be great, if you add a config to turn off the monitor immediately after the screen was actively locked. Most of the time the computer won't be used soon after the screen was locked (e.g. by using a keyboard shortcut). Energy can be saved if the screen turns off immediately instead of after the default timeout. I think, this behavior can be configured on Mac books (but I'm not sure).
After locking the screen using a keyboard shortcut, the screen keeps turned on for the default duration, that is configured in the energy settings.
It was great if the screen turns off much earlier.
Linux/KDE Plasma: Arch Linux
KDE Plasma Version: 5.22.4
KDE Frameworks Version: 5.85.0
Qt Version: 5.15.2
*** This bug has been marked as a duplicate of bug 348529 ***