Hi Yoel!
I'm not sure my approach here will be very useful. I didn't use Godot's built in high level API for multiplayer, just raw web sockets and a proto-buff plugin (I think this one https://github.com/oniksan/godobuf) Most of the actual game logic for the game is on a go-lang server. I think this is the reference I used for implementing the websockets in Godot https://docs.godotengine.org/en/stable/tutorials/networking/websocket.html