Under Settings, Control Center, Regional & Accessibility there is a menu called, "Keyboard Shortcuts." I found an entry called, "Toggle Showing Desktop" and changed the shortcut to F4. All I have to do now, to minimize ALL windows, is press F4! It's easy! I even removed the Show Desktop icon from my Panel - no need for it there - as pressing F4 is easier than looking for an icon to click. F4 and Show Desktop. Even more control over your computing experience. Isn't this cool?
Yes it is. In fact, if you are a CLI person like me, you'll love fooling around with those settings.