from my side I have been trying to make SIM7080G to connect to AWS IoT Core but it was really useless because my firmware version did not support the MQTT(S) protocol that AWS IoT Core requires to connect with your device.

Solution 1 is to try to update the firmware of your SIM7080G to the latest that supports MQTT(S).
Solution 2 is what I followed. Create an EC2 that hosts Mosquitto and a script to bridge the 2 layers the device and AWS IoT Core.
Device sends MQTT 1883 - > EC2 Mosquitto forward with MQTTS 8883 -> AWS IoT Core receives
AWS IoT Core sends MQTTS 8883 -> EC Mosquitto forwards with MQTT 1883 -> Device MQTT 1883 receives