Thanks @HurstOlds , happy to see that someone else than me use it 
This is typically the best feedback that we could expect when we work on this kind of project 
Good news : you can now declare MrDiy Notififier as media player in Home Assistant so sending TTS to the notifier is even easier.
This new feature is in progress, not sure which MQTT media player I will use at the end but for now it’s starting to work with “media-player-template”, see my post about it here (still in progress…).
May be the Notifier status would be easier to retrieve with hass-multiroom-mqtt-mediaplayer or hass-mqtt-mediaplayer… We will see that later …