I hope your issue with the SIM7600CE-T 4G(LTE)Shield is solved now. However, you can also  consider using SIM7000. 

Many 4G LTE-based projects can be done with this pretty well: 

https://www.pcbway.com/project/shareproject/4G_LTE_TempSensor_v1_2_SIM7000_74f64b71.html

It should be possible but you may need to make your own library.

I think it is better to follow the wiki page setup first: https://wiki.dfrobot.com/Voice_Recorder_Module_Breakout_SKU_DFR0745

I do not think replacing the module is a good idea. Even if you succeed in replacing the ESP32 module, the Firebeetle may not function. 

You can buy a separate  ESP module according to your requirement: 

https://www.theengineeringprojects.com/2021/08/esp8266-based-wifi-modules-for-iot-projects.html

I think you need to use an I2C multiplexer. 

https://www.dfrobot.com/product-1780.html

Maybe there was water on the sensor's body or something like that. Maybe the readings were effected by its surrounding. 

You can use shift registers (e.g., 74HC595) to expand the number of output pins.

Try to test the 9-DOF ICM-20948 sensor separately. If possible with an Arduino UNO. 

Check if there are any sources of signal interference between the HuskyLens and Arduino, such as other electronic devices or long wires. Minimize interference to ensure reliable communication.

Please check all the wires and joints.

Maybe a faulty board. Did dfrobot contact you in this regard?

Dfrobot should fix it soon.

Hi, what power supply are you using?

What type of color papers are you using now as your samples?

Utilizzare un adattatore CC da 5 V, 2 A.

Hi, did the above instructions solve the error problem?

The final output value is affected by probe insertion depth and how tight the soil packed around it is. We regard "value_1" as dry soil and "value_2" as soaked soil. This is the sensor detection range. For example: Value_1 = 520; Value_2 = 260. The range will be divided into three sections: dry, wet, water. Their related values are:

Check if the depth or tightness is varying. 

What was the solution? May I know?

Here is a discussion regarding the same error message: https://forum.arduino.cc/t/a-fatal-error-occurred-failed-to-connect-to-esp32-no-serial-data-received/1071486