Ok… I found a solution… Not a keyboard shortcut, but it’s now in my Standard toolbar, accessible with a single-click. [The right-click select is a pain, when you deal with muliples per day] [Search for “Add a button, menu, or command"
Here's how to customize your toolbar..
go to VIEW…TOOLBARS…CUSTOMIZE â€
Under COMMANDS, select Actions… Scroll until you find the “ADD SENDER TO BLOCK SENDER’S LISTâ€â€
Click that option and literally drag it into your main toolbar. You’ll see a “+†sign when you get to an area where you can drop it
Hope this helps