Hi @brianmoon welcome to the forum.
You might want to look at this How to get the best from this from this Forum before you proceed any further.
It tells you how to post code.
It seems your problem is because an ESP32 processor works off 3V3 where as an Arduino Uno works from 5V.
That means while a Uno can measure a voltage up to 5V, the ESP32 can only measure a voltage up to 3V3 before it saturates and shows the value is a maximum of 3V3.
You need to use a voltage divider to cut down your input signal from 5V to 3V3 before you feed it into the ESP32.