My first attempt at a Muteomatic Toggle macro held the left click in the middle of the Muteomatic circle. This worked, but the held click stopped working as soon as the mouse was moved - even a tiny movement.
My second attempt simply clicks the Play and Stop icons. I think this does what you want, but I don't have the equipment to set up a Talkback channel, so I can't fully test it.
The macro uses the "Click at found image" command, using screen shots of the Play and Stop icons.
I originally used the complete icons (with the surrounding circles), but this confused the macro - sometimes the Stop icon was clicked instead of the Play icon. I don't know why this happened - I never seen the problem before.