he still had to connect the Ethernet side of the PoE device to the Waveshare LAN8720 board that’s providing Ethernet for the ESP32. So he removed the RJ45 jack from the LAN8720 completely ...

This open-source gem uses the wESP32 board, which combines an ESP32 with Ethernet and Power over Ethernet (PoE) for robust, reliable connectivity. Check out the Crowd Supply campaign for details.