In the before times we would make something called a crossover cable to allow two network cards talk to each other without a switch or hub between them.

Void and time crystals obviously. And novelty portable holes by acme

The wall mount rack is a used ACP Netshelter. I was able to find it on Craigslist a few years ago. The rackmount face plates are custom 3d printed but unfinished as I abandoned the project due to life.

I have 2 of them with older 6 core CPUs and 32gb each. I also added a 10g SFP card in the PCIe slot so they would have a bit more umph.

For 380 each I would not bother, and I would look at the Minisforum MS-01 as it has built in dual 10g SFPs and dual 2.5g RJ45’s plus a PCIe slot.

https://minisforumpc.eu/products/ms-01?_pos=1&_psq=MS&_ss=e&_v=1.0

at ~80 euro’s more you get more CPU, faster ram if you can find it, more storage, and more networking.