I’d return that unopened, chances that it will work or work well are slim to none.
FreeBSD Ethernet drivers are not as varied as Linux ones. Realtek chips don’t work well at all, Intel does but there are exceptions as you found. Chelsio is supported well on 10G, and after that it gets a little sparse.
Here’s a server NIC for 20:
https://www.ebay.com/itm/Orginal-In...120584&hash=item2aec5a7d09:g:UrAAAOSwjZ9fAoEr
And the same idea quad port:
Find many great new & used options and get the best deals for DELL INTEL PRO/1000 VT PCI-E NIC 4-PORT GIGABIT SERVER ADAPTER EXPI9404VT YT674 at the best online prices at eBay! Free shipping for many products!
www.ebay.com