is 4G available?
not used the Mkr Nb 1500 but have used the MKR FOX 1200 which works OK with the Arduino IDE and associated libraries - maybe worth posting in the MKR 1500 forum?
Mkr Nb 1500 is a bit expensive (approx £80 in UK) compared with the TTGO LoRa32 SX1276 OLED (approx £20/£30 in UK) - the LoRa configuration could be cheaper using seperate ESP32 and LoRa modules but you then have the problem with interconnecting wires
if you go for LoRa check the frequencies for your country