What’s the disadvantage of turning it on by default compared to “Leave unchanged”?
With Xorg you have numlockx to force it on. I don’t know what wayland has.
The advantages or disadvantages depends on your personal preferences.
the problem is, I guess, it still doesn’t work
For KDE, there is a setting to turn on num-lock by default. Search for “Numlock” in System Settings.
Courtesy of the Arch Wiki
Go to System Settings > Input Devices > Keyboard, in the Hardware tab, in the NumLock on Plasma Startup section, choose the desired NumLock behavior.
thx, I guess that works but it doesn’t pass the argument to SDDM
Thx. Having a look into the issues about numlock it appears someone also wanting to have it enabled by default 432294 – Numlock is disabled by default on login screen
And here’s a recent bug report 477374 – Plasma on Wayland fails to recognize numlock status on startup
In Fedora 39 Cinnamon, search for numlock yields nothing.