This is really lame to suggest, but I had an old Mac Mini that had a dead NIC, and I also had a USB NIC, and it ran that way for god knows how long...
Maybe 20$ and keep using the Mac Mini?
I have an old Lenovo Tiny that's running a few Docker services. It's an i5-4570t, I think? It sits in my closet next to my router and is probably covered in dust.