I made a little LoRa Modem, using the RAK RUI3 AT Commands as a guide. I implemented LoRa and FSK but not LoRaWAN. There are some example scripts, one for sending a file from one unit to another, as well as a script to spy on Meshtastic packets.
You can find them on my website:
Heltec v3 - Heltec v4 (tested on v4.3)