This thread has some good info for a downlink setup.
.Ideas on beefy offline render? - #6 by brunobg
For uplink, you will have to forward events from the client to the server.
Getting this working would be awesome, because you could use babylon without arbitrary limits imposed by chromium. Uber is doing something like this with their gis analytics
This could be worth checking out, as a kind of replacement for puppeteer
.https://github.com/node-3d/glfw-raub