Why can't I make any kind of keyboard shortcut to turn on and off Voice Control?

This has been an hour of digging... As someone else said with the same issue: for an accessibility function, this is wildly inaccessible.

I want a single keyboard command, even one I *invent*, to toggle the Voice Control function on and off. I do not want to use Siri or go into the maze of System Preferences. I do not want a 'Shortcut' -- there's no way to make that into a keyboard shortcut (I've discovered) either.