Godot has a nice netcode story with ENet, WebSocket and WebRTC integration. If you just want a off-the-shelf product instead of bespoke Erlangy stuff, I think there are a lot of good options out there like Godot's native high-level networking, products like Nakama, etc.

Server backend framework: https://github.com/saltysystems/overworld

Chat server implementation (Erlang): https://github.com/saltysystems/chat_server_example

Chat client implementation (Godot): https://github.com/saltysystems/chat-client-example