Sonoma has this feature i’m really starting to like where you can left click anywhere on the desktop that is visible and it does a show desktop action. I think this actually used to be possible back in KDE4. But I can’t find a way to do it in KDE5/Plasma. Didn’t there used to be a Show Desktop containment action?
You can enable a screen edge or corner to do that if you would like an already available alternative:
System Preferences > Workspace behaviour > Screen edges
U can add an widget on ur panel to peek at desktop or minimise all windows. Both of those widgets are available. Very very handy if u keep it either at the right or left most in ur panel.
This is smoother than finding a space that is visible in desktop. Eg: I have a panel at bottom and that widget is in the right most corner of my screen so all i’ll do is just move cursor to the bottom right of the screen and left click. It’s super fast.
And f u want much more easy way just use screen edges just like someone instructed above. That’s very cool too