The ESP32 contains an Ethernet MAC. To use Ethernet you need to add a Ethernet PHY IC. The Espressif standard solution is based on using a TLK110 Ethernet PHY which is quite expensive. The LAN8720 is a much lower cost option that can also be used.
ESP32 Boards with Ethernet
https://www.olimex.com/Products/IoT/ESP32-GATEWAY/open-source-hardware
POE Resources
https://hackaday.io/project/85389-wesp32-wired-esp32-with-ethernet-and-poe