Domoticz

I have a ESP8266/32 mesh network connected to Domoticz (mainly dummy switches) and when a node is responding to change in Domoticz GUI an 'ack' is sent back to ensure that command was received ok. I can update a dummy text via Json command to visualize this but would rather use the small OSD that shows up when a command is sent from Domoticz.
Is there a way to show this OSD with text of my own?
Amy help appreciated

You could have your devices report their current state every for example 2-5 minutes back to Domoticz so in Domoticz the widget is showing the correct state.
So when the command is not received the widget is put back to the original state.

In real mesh networks like zigbee or zwave (never heard of your type) there is a controller that sends the command and asks for a ack and if no ack the controller will report that back to Domoticz.

Additional: Currently when you switch a light from the web UI you get a short popup showing switching on, off.
I have never seen an ACK popup to acknowledge that command. Neither an Error popup.

So probably not available in the source code of Domoticz or in the Python Plugin Framework.
So to have a popup message with the Ack you will have to add something to the source code. With C++ programming skills this is possible. Check the GitHub repository of Domoticz.