Cannot set shortcuts

I just installed Manjaro KDE and I need to set the application launcher to the super key, but anytime I try setting a shortcut (anywhere) I keep seeing Henkan key pressed

So, you are using a 109 key Japanese keyboard with the five extra keys (backslash, yen-sign and the three
henkan keys around the spacebar), which do not produce any kind of input unless in combination … right ?

Might have to go trough this and see what helps to adopt it to KDE Plasma.

See also this

No, I am using a 104 key English keyboard and I don’t even know what a Henkan key is