Reticulum is a full network stack with full user anonymity. You can integrate it in every app that needs P2P network connections and that can live with a slow connection. Reticulum is an alternative to TCP/IP and UDP/IP, using a mesh.

Meshtastic and Meshcore are mesh messengers, focusing on mesh text messages.

meshtastic is chat and lora only. its protocol is super inefficient and unreliable, and only can handle a maximum of 7 hops across the mesh.

Give a try to Meshcore, their design has proven to be reliable in realworld use.