So... I just set my keyboard in KDE settings to Dell Latitude(i have a dell latitude) and now i can press the volume keys and they work, and pressing fn lets me press F* keys. But, my menu doesn't open. I've set it to alt+f1, alt+volume mute, and meta+a, but no luck. I am on plasma 5.24.7, using trisquel gnu/linux(triskel variant). I am using X11.
sometimes a hangup in a widget or other taskbar or desktop customization can freeze up the menu. right click on the taskbar, enter edit mode, and resize the taskbar height one up and back down to where it was. if that doesn't fix it maybe remove any widgets or other customizations.