Another macro leveraging KM's Prompt With List function and Applescript. Obviates any interaction with the Music app's UI, too.
PLAY PLAYLIST (SHUFFLED).kmmacros (4.5 KB)
Macro is pretty self-explanatory. Gets a list of your playlists, asks you to choose one, then plays the selected playlist, shuffled. Prompt action helpfully narrows down list as you type input. Prompt action's default input is the previously chosen playlist. If you put "all:" into the default answer box, it will list out the playlists.
The AppleScript can be tweaked to omit "set shuffle enabled to true" if you don't like that part of the macro. If you want to toggle Music's shuffle feature, you can use the following macro, if you like - very simple AppleScript:
SHUFFLE TOGGLE.kmmacros (2.6 KB)