I was wondering if you'd seen these boards?
https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_201712310…
It's a SX1278 all soldered together on a ESP32 board for about $10
Would your software run on it? Or would it be a lot of work to port?
https://www.cnx-software.com/2016/03/25/esp8266-and-esp32-differences-in-on…
Someone has done chat over it:
https://hackaday.io/project/27817-lora-chat
There is some info here:
https://hackaday.io/project/27791-esp32-lora-oled-module
I might order a couple to play with
Thanks
Sam