Unlike tailscale/ngrok, malai is completely open source, does not rely on any company provided infrastructure (we have a http bridge to bridge http/tcp with http/kulfi at *.kulfi.site, but you can run your own http bridge), and once Kulfi app is ready, you will not need the bridge at all and Kulfi app (which is also basically a browser that speaks http(s) over kulfi along with http(s) over tcp) can talk kulfi protocol directly.
Yes, we are currently using iroh provided relay servers. malai will soon connect with any relay server, so in future you can use ones provided by us, or run your own.