You can access the menu by keyboard with Ctrl-F2, but it isn't exactly what you want; that said, a nifty property of macOS is that you can modify the keyboard s

You can access the menu by keyboard with Ctrl-F2, but it isn't exactly what you want; that said, a nifty property of macOS is that you can modify the keyboard shortcuts if any app--including adding shortcuts for things that don't have one--in the Keyboard Shortcuts settings panel under App Shortcuts (it works by doing a string match on the menu item name).