I think I'm almost there. Just need help to figure out the abort().

#include <TinyGsmClient.h> 
#include <PubSubClient.h>
#include <WiFiClientSecure.h>

• I establish LTE-m connection with TinyGsm.
• Configure the MQTT.
• Generated a SAS as MQTT password.
• Make a secure SSL with root certificate WiFiClientSecure.

But when I call mqtt.connect(DiviceID, MQTTUser, MQTTPass)
I get an abort :

assertion "Invalid mbox" failed: file "/home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/eip/src/api/tcpip.c", line 374, function: tcpip_send_msg_wait_sem
abort() was called at PC 0x400d80e7 on core 1

The full code is a bit lengthy so let me know if you have experience with this. and i will post it.

Yes and No, you can activate the GNSS (GPS, Galileo..) and ask for the GNSS info (from cold start it me take a while to get position data). And establish a connection with GSM/LTE simultaneously. (As in they can run at the same time). The AT-command to receive data can be called fast after one another, but not Simultaneously.

// GSM/LTE
AT+CGATT=1
AT+CGSOCKCONT=1,"IP","YOUR ANP"
AT+CSOCKSETPN=1
AT+NETOPEN
AT+IPADDR
AT+NETOPEN? //+NETOPEN: 1 is net open
// GNSS
AT+CGNSPWR=1
AT+CGNSINF

I'm using the Lilygo SIM7000g.

In my case I can power the board with the 3.3 pin but only if the voltage is higher than 3.7v. I also used 5v in the VIN pin and let it run for a while. But when the voltage did go up to 6v I broke something.

So you can use the board without battery, I even broke the 18500 of the board.

Does someone know what fuse I need to replace from the VIN pin? Schematics I count find it.