I am trying to make a hotplate with an ESP32 and I use MC34063 for buck/boost converters. The hotplate itself require 12-30V to operate and the ESP32 and LEDs need 3.3V.

Here is the circuit:

When the circuit is powered, I hear (almost) nothing while the ESP32 is booting but after that, I can hear an annoying audible noise. I tested with an oscilloscope and the output of the MC34063 seemed to have a frequency between 10 and 15kHz.

I have already checked this question but it does not seem to have a complete solution for my case.

You can find the complete schematic here and the PCB here