KDE meta key not working

## The issue There are several questions that I can't find an answer for about the Meta key on KDE. 1. What is the Meta key mapped to by default? 2. How to know to which key the Meta key is bound to? So I tried to bind the Meta key to various keys: Alt, Win, Left Win but the Meta key doesn't work. What I would like to do it bind the Meta key to the Left "Windows" key. So I saw in xev how my Left Windows key is recognized:

KeyPress event, serial 36, synthetic NO, window 0x6a00001,
    root 0x7b7, subw 0x0, time 10281010, (167,-9), root:(2958,436),
    state 0x10, keycode 133 (keysym 0xff20, Multi_key), same_screen YES,
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False

KeyRelease event, serial 36, synthetic NO, window 0x6a00001,
    root 0x7b7, subw 0x0, time 10281090, (167,-9), root:(2958,436),
    state 0x10, keycode 133 (keysym 0xff20, Multi_key), same_screen YES,
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False

Then I tried to manually bind that key to Meta in KWin config with:

kwriteconfig5 --file kwinrc --group ModifierOnlyShortcuts --key Meta "Multi_key"

So this command is just adding the following lines to ~/.config/kwinrc

[ModifierOnlyShortcuts]
Meta=Multi_key

PS: I also tried with 0xff20 instead of Multi_key Then I force relaunching Kwin for the configuration to be taken into account.

qdbus org.kde.KWin /KWin reconfigure

But it still doesn't work. This annoying because many shortcut are using the Meta key and also so default behavior like opening the menu are not working (while Alt+F1 does). I also spotted that when I tried to use the left windows key in a shortcut I have this strange stuff instead of Win, Left Win, Multi Key or whatever it is supposed to be. ## Environment information

Operating System: Arch Linux
KDE Plasma Version: 5.25.5
KDE Frameworks Version: 5.98.0
Qt Version: 5.15.6
Kernel Version: 5.19.8-arch1-1 (64-bit)
Graphics Platform: X11
Processors: 8 × 11th Gen Intel® Core™ i5-1145G7 @ 2.60GHz
Memory: 15,4 GiB of RAM
Graphics Processor: Mesa Intel® Xe Graphics
Manufacturer: Dell Inc.
Product Name: Latitude 3420