https://www.truenas.com/community/threads/what-kind-of-nic-do-i-have.92464/

You have a Realtek in there. If you look with “ifconfig” you will find your ethernet is an “re0”, and the 8111 is a highly problematic beast. Sometimes they work, more often, not.

The Realtek is so bad that we normally just tell people to go buy an Intel CT Desktop adapter, which usually brings joy to their faces after failing to figure out any tweaks to help their impaired ethernet adapter. But, mini PC.