I just setup the node-red-contrib-google-home-notify-volume-adjustable in my installation.
It is broken with error message in the debug window "TypeError: Googletts is not a function" when I googled this seems that the node is broken and no longer being updated by the contributor.
I do like however how you have mentioned the use of using the announce instead of cast which I am currently using for my doorbell which currently annoyingly stops the music from playing as I shake my fist at the person at the door for interrupting my beats.
