Your shell output shows that the connection from the frontend is detected and that the frontend is asking for the server config. But because no additionals verbose logs are shown I think the .env file is not imported. It should be located at the same folder where config.js and server.js are.
If it does not work with the env file, you could change all defaults in config.js (if not using the Windows or Mac executables).
youhooo !
Its working.
Switching to lw.comm-server repo did the job.
USB port now shows all my connected devices.
here is my setup. I can now controll my 3D printer (via octoprint), my ortur LaserMaser2 (via LaserWeb) and other stuff from my RPI3 server.