2G FONA-era boards, LTE Cat 1/Cat M1/NB-IoT modules, and M.2 Cat 6/5G modems target different networks and hosts. Check carrier sunset and bandwidth tier before ordering.
Adafruit FONA GSM breakouts, the Gravity Air780EU 4G Cat 1 module, Dragino NB-IoT Shield-B8, Pycom FiPy, Quectel and SIMCom M.2 5G modems, and the RockBLOCK 9603 Iridium modem each target a different network tier.