You know what is proven effective? Not needing to reach for a mouse to interact with taskbar, start button and menus. GNOME is extremely effective as long as you aren't a clicker. If you want to stick to a 30 year old desktop metaphor that's on you but the rest of us have moved on.

Discoverable user interfaces are orthogonal to keyboard interaction efficiency.

Menus are one of the primary ways you can discover keyboard shortcuts.

I often see people praising gnome for it's keyboard efficiency but they are not even 10% as good as macos.

If they cared so much, they would have keyboard shortcut for everything, in every app, with the top bar displaying menu and every shortcut attributed to it, just like macos.

Instead you can use the keyboard to switch an app, close it and so on but once you are working inside, you immediately need to take your mouse. What's the point ? It saves 1 second and confuse lot of beginners.