Understanding messaging between devices

I need help understanding the messaging between devices and apps when doing automation tasks. In particular, let me ask about Alexa.

This is what I think happens. Is this correct? When I say Alexa turn on the plug", The Alexa pod hears the wake word and sends the voice to the Amazon cloud program that determines what to do. The Amazon cloud program then sends a message to the Smart Life App, in the cloud, and the Smart Life App send a message to the plug to turn on. Obviously, the Alexa Cloud program must send the name “plug” to the Smart Life App. Then the Smart Life App send a command via wifi to the plug. If the plug responds, then the Smart Life app sends an acknowledge back to the Alexa cloud program which sends an acknowledgement chime back to the Alexa pod. Is this correct? Assuming so, where are the MQTT messages being sent if at all.

Now the puzzling question is why if I give the same command to myh Google pod, the plug works also. I have never linked the plug to my google home systgem. Does Google somehow also send the command to the Smart Life app? I am puzzled.