Gotta say I expected this to be the wifi system. Most of the code on the ESP-32 is given as source, but the wifi driver is not.

https://github.com/esp32-open-mac/esp32-open-mac

the lower layers of both Wifi and Bluetooth on ESP32 family devices are closed as of this writing.

Anyone who has thought critically for a few seconds has suspected this. The question is whether you're right and if you can prove that.

That doesn't match the article at all.