Agro-precision project not being precise - Fixing SS200 design

This project is about measuring the amount of water in agriculture's soils using a matric potential sensor (200SS), a DS18B20 temperature sensor and an ESP32. It's an IoT development so the system is connected to the cloud, also has a LoRa module to communicate with the gateway and it's feeded using a PV solar panel.

The overall project is not working as expected and I'm suspicious that something in the PCB is not correctly design, because I've tested the entire script (and by parts) using ESP devKits and it worked fine. What I'm most concerned about now is getting correct measurements from the 200SS sensor.

So I'm looking for someone experienced who can get deep into my PCB design and get the SS200 sensor measuring perfectly and also get some good electronics practices into the design. I can work side by side, when needed, via videoMeetings testing new versions of the hardware and I'll provide all the relevant info in order to get my expected results.

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The main materials are:
- ESP32-WROOM-32 programmed in Arduino IDE
- DS18B20 temperature sensor
- 200SS sensor + 74HC4051 MUX module + BJT + MOSFET for reading circuit: https://www.irrometer.com/200ss.html
- SX1278 LoRa module
- MT3608 booster + TP4056 battery charge + S18650 solar battery
- DS3231 RTC module