While the Arduino-ESP32 side is my main focus, the ESP-IDF build ought to be very similar (demo*.ino --> main.cpp, and the header and source libs aren't in their canonical locations by default).

An Arduino library for the u-blox SARA-R5 LTE-M / NB-IoT modules with secure cloud, as used on the SparkFun MicroMod Asset Tracker, the SparkFun LTE GNSS Breakout - SARA-R5, and the SparkFun MicroMod ...