pop up menu/pie menu for shortcut keys that are assigned to multiple operations (quick favourites on steroids)

When you add a shortcut and use a key that is already in use, in 2.9 nothing happens, the shortcut isn't added, and there's no message to tell you why.

It would be brilliant for many reasons if the one shortcut key could be assigned to multiple operations. Then if the user clicks that shortcut, a pie menu pops up giving the user a choice of which operation they would like to perform. If more than 8 operations belong to a single shortcut key, then a standard pop up menu would be displayed instead of a pie.

One big benefit of this is that you could much more easily remember shortcut keys, because there'd be far fewer to remember, plus because there are fewer shortcut keys, you could map them all in closer proximity of your hand rather than reaching all over the keyboard.

It should definitely have the ability to have multiple levels, so you could add shortcuts to top level UI menus, like the align view menu found in the 3d viewports view menu for example.