One of the best things about ESP32 is that the ARduino layer is just a compatibility layer. I ported Zork to FreeRTOS and booted it natively as a FreeRTOS app on the ESP32, that was massively educational.

AFAICT basically nobody is using python to program these things, just C. Building my own breakout board is crazy. But my friend did build an Arduino from scratch on a breadboard from AVR, etc. Don't see the point- that's all work that doesn't bring me closer to driving my 3D printer.