Amazing, I knew something bizarre like this had to exist. Thanks for the keywords!

This one has two ports:

https://www.amazon.com/CREST-SI-MPE24046-Gigabit-Ethernet-Interface/dp/B01N9HNXBB

It appears to be a RealTek chipset, but not sure if it's an awful one or not. One Q&A answerer there claims it works with pfsense.