I2C communication between Arduino Uno and Nodemcu32-s (ESP32)
I'm working on something similar at the moment. Not a complete answer put some thoughts:

Have you considered that the Uno is a 5v board and the ESP32 is 3.3v? You may need a signal level shifter (there are many to chose from) something like Pololu-2595 which is breadboard friendly.

There's a good ESP32 I2C explanation at Random Nerd Tutorials.