nice use of WebRTC, which somehow is still underutilized.

>If you're self-hosting and you want to access the signaling server remotely via mobile data, you may need to set up DDNS and port forwarding if your ISP provides a dynamic IP.

this also exposes your server to the internet. instead you can use one of the open source solutions which creates a private connection between your Pi and server (so there is no network access to the server - make it unreachable), and doesn't require static IPs or port forwarding.