Long range (LoRa) mesh networks are interesting alternatives to communication, especially when state actors are blocking internet access for various reasons.
More details about meshtastic: https://meshtastic.org/
About its current state of encryption: https://meshtastic.org/docs/overview/encryption
Not sure if they’ve improved it but meshtastic also used to require a module per device/phone so sadly you can’t dot them around and allow multiple people to share them like with group events.