Not to take away anything from the fun of figuring out Thunderbolt on Linux, and such. But, I wonder if a NAS with a 40 Gbps or even 100Gbps NIC hooked up to a Thunderbolt to Ethernet adapter would achieve a better result without extra effort.
The dongle is QNAP QNA-T310G1S Thunderbolt 3 to 10GbE Adaptor, US$169 on Amazon.
For other devices in the network that do not impose Thunderbolt though, Melanox 40G NICs are surprisingly cheap.
The cables and cards for PC Thunderbolt retrofit are far (like 3-5X!) more expensive than the MLNX cards and optical cables.
$0.02 :)
I added new Thunderbolt3 PCIe cards (Gigabyte Titan Ridge) to two of my 2012 Mac Pros for around $100 each a bit over a year ago and the prices have dropped since, so I don't get how that is 3-5x more expensive than MLNX cards. Expense was way way lower a factor than the finesse it took to get MacOS to support them for me, but it was the only path that worked for my needs (different need than OP article) and so I endured the pain of getting it working.