A messaging app/service that can work via both regular stable connections but also via non-online. Briar is kind of similar to what I am talking about. But it can't/doesn't go as far as I mean. It can send messages via cell data, WiFi, and Bluetooth but as far as I am aware, it can't do a mix of them. And it would still require the person being messaged to be within range of my phone's Bluetooth if not on cell/WiFi. So it doesn't do the hopping I am really interested in (to my understanding).

So I am wanting to be able to have basically zero cell or WiFi signal on my phone, but be able to just have shit be able to bounce around via all methods to get to the person I am trying to reach. So like I could be in a no service spot for my carrier but maybe a friend that also has the app and does have a signal be used to bounce my message from Bluetooth to their cell or WiFi that is working. Then it either get to the final person from that bouncing, or maybe still get it if they are also in a no-signal area but still near another friend that does and is also in their Bluetooth range.

So the message would just hop whatever chain of devices and connections even if it takes a little more time (like if it just had to keep hopping from a number of phones completely through Bluetooth jumping. Would also be cool if it could jump even if the other devices didn't have the app and was just encrypted text-only blobs hopping like how data hops around various servers when online. But aside from the fact that data costs money and would mean basically everyone's shit would get used at all times. The nightmare of how the messages/service would know how to get places, or if maybe it already arrived via one method while a different chain was still trying would be massive. In addition to literally all the other things that would have to be figured out. And that is all before making sure it could be still private in any real way.