I was initially optimistic about Bitchat but after investigating it does just seem to be an early hobby project. We need more than individual apps meshing via Bluetooth. I’m doubtful Bitchat will ever be used outside of a group of nerds at a festival.

We need a standardised protocol commonly implemented by manufacturers. The closest we have now that I’m aware of is Apple’s Find My network in which it is possible to smuggle arbitrary data very slowly. [0]

[0]: https://github.com/positive-security/send-my

This is the second comment that mentions Find My. Find My just sends data from BT beacons to Apple, it's not a mesh network at all.