nice one…
snapcast seems to be nice but I really want a lot of speakers for a small price when I think to the topic “multiroom-speaker”. There are some dudes playing with the idea to bring a snapcast-client to an esp32. But at the moment it seems to be a device like a pi-zero, or am I wrong?
I really like the idea of Squeezebox wich is an openSource multiroom server/client by LG. Some people in the slimdevices community bring the client to a tiny, cheap ESP32-WROVER-IPEX and combine them with a I2S stereo decoder. Like this one.
The user philippe_44 create a pcb for this, what looks awesome:
https://i.imgur.com/wsuUiIc.png
Source in this post.
Perhaps I need to try it on my own after do my soldering job 
When I remember back to my bad-google times I can remember that they implement this by:
“Hey Mycroft”, “Play blabla from youtube on device loudsprecher”