[0] https://www.shi.com/Products/ProductDetail.aspx?SHISystemID=...
https://www.cdw.com/product/exablaze-exanic-x10-network-adap...
Ultrascale. Significantly cheaper. Could it be made to work out is it subject to your comments concerning kintex, pcie straddling?
Aside from that did you know you were going to do this when you did verilog-ethernet etc?
But Netronomes are remarkably cheap, and you can "offload" eBPC to run on the card's custom cores.
[0] https://www.shi.com/Products/ProductDetail.aspx?SHISystemID=...