I finally was able to disable the LoRa-E5 extreme low power mode via a terminal sending the following command via a FTDI connected to the Grove LoRa-E5:
0xFF 0xFF 0xFF 0xFF AT+LOWPOWER=AUTOOFF.
Now I need to figure out how to turn off the extreme low power mode in Arduino code in the microprocessor connected to the LoRa-E5 module.