Data Streaming from Unity VR app to mobile (iOS/android/web) client

I've abandoned trying to do it with Unity's networking. I can make TCP connections between a react-native mobile and a unity build for the headset. I had to hack it together by logging the IP address of my headset and entering it into the mobile app. I'm struggling to find a good way to discover devices on a network. It would be awesome if I could use iOS's Bonjour or Androids NSD, but I'm kinda blocked on how I might run the Java code required for Androids NSD because I couldn't find any C# libraries for it.

I made an algorithm that discovers devices on a local network that are listening to a certain port. I got the IP address and Subnet from Node.js (os module). Then, used npm's NetMask to find the network address and I just iterated through every available address attempting to make connections. The next step would've been sending a handshake, so I can tell if the listener was a device that I programmed.

This is a bad system though because you're not guaranteed to be allowed to listen on the same port every time the app runs, and I worry about how flexible this system is on networks with different configurations.