As has been pointed out in other threads, the ESP32 micro-controller used is an extraordinarily poor choice for miners. It is made for use in very simple IoT devices such as sensors, thermostats, wearables, etc. that do not need good performance. Even the maker of them clearly states that. Even the best one only has 2 cores/threads which means that at best it can process hashes and do I/O without having to interrupt the processes provided the main and I/O threads are programmed to run independently. AFAIK the one used in the BitAxe has only 1 core...

All of that out of the way, does it work? Sure - but when there is a change of work and when it talks to the WiFi things slow down a lot. Because Skot is/was an IoT developer it makes some sense that he'd pick the ESP32 just because he is familiar with it. Unfortunately he did not know that you REALLY need a REAL multi-core/threaded CPU to ensure decent performance so the various processes running do not have to interrupt each other. Even the original RasPi-1 used a more capable chip.  ref https://www.elprocus.com/difference-between-esp32-vs-raspberry-pi/

FYI, while the 1st ones from Sidehack will be using the same micro he is already redesigning it to use the Pi Nano to eliminate the processing bottlenecks and also allow using USB along with hardwired LAN connections.
edit: struckout comment on redesign.