Hmm... I'm pretty sure MURS allows for this type of traffic as of the last rules revision and would be ideal for this use with the higher power allowance, but MURS is a USA only thing so that kinda limits you if the goal is something that works all around the world.

OP is also talking about using off the shelf LoRa boards and their project is more about the software, so they are stuck with the bands available on the commercial LoRa transceivers those boards use.