If you are using an MCU to measure soil moisture, you don’t need an external IC. You can do it with the MCU alone. I can show you how.

For electrodes, use platinum wire or graphite.

Platinum and graphite are not easily manufacturable for the board. The manufacturer I'm currently using is JLCPCB and they don't offer platinum or graphite. Also, the reason I'm using an IC is to make the board more modular, that way when I add more sensors on the board they can all share the SDA and SCL lines instead of each have a separate analog output line. I do know how to use the ADC on the ESP32, but I'm simplifying it to minimize wires, and save on costs.

 

Maybe consider adding the IRQ functionality?