Smooth zooming with windows/meta/super key + plus or minus does not work

I am trying to set up a gesture for smooth zooming. At the moment, I am binding libinput-gestures 2-finger pinch with Control+0x002b and Control+0x002d but these gestures are choppy as they are just the equivalent of Ctrl++ and Ctrl±. Then I find this thread 2-Finger Pinch Zoom Gesture not working smoothly on KDE that tried to do exactly the same, but in my keyboard pressing windows/meta/super key + plus or minus does nothing. How do I resolve this and get smooth zooming to work with gestures?

Did you set in Settings > Shortcuts > KWin > Zoom to match the shortcuts? Is the Zoom Desktop Effect enabled? You can set there the shortcuts too …

I check that setting in KWin they are already set to Meta+= and Meta±. I don’t remember doing this, it looks like it came preset with the system. But this makes me wonder though, which setting is it then which uses Ctrl+= and Ctrl±, the ones that work.

EDIT: I see, you have to enable the Zoom Desktop Effect. The Meta+= and Meta+ - now work, however it turns out to be not what I really want. Those zooms zoom in and out the desktop, not the same area that Ctrl+= and Ctrl± affect.