Think there is more capable technology out there?
Like LoRa (short for Long Range)
https://en.wikipedia.org/wiki/LoRa low power wide area network stuff. Each device has GPS and a LoRa radio. So each device knows where it is, and can talk to other LoRa devices in range (or out of range as long as there are other LoRa devices to forward on the message).
But not there yet as a usable off the shelf product for regular folk to use.
Most seem to be buy a bare electronics board (<$30) with some soldering possibly required.
There is a Android phone app that allows you to pair your LoRa device with your phone.
https://www.meshtastic.org/