Setting things up was straight forward, the process is no different to building a commercial or workstation platform. The 7773X machine runs Window 10 and I have another 7452 QS machine that runs Ubuntu. Both are mostly pain free. I have EPYC boards from both Supermicro and ASRock. I find the ASRock board to be more "modern" and has a better BIOS, but Supermicro has slightly better community and official support. In the very early Naples era AMD's BIOS had some GPU compatibility issues, but I think nowadays you can use any GPU you want.
You can get very cheap Genoa engineering samples or qualification samples off eBay so you can skip the older DDR4 platforms. Their sockets are very different, you wouldn't even be able to reuse the heatsink.
One thing to watch out for when buying EPYCs is to definitely avoid vendor locked CPUs. Any EPYC CPUs once installed in a DELL or Lenovo board will be physically altered forever to not be able to boot on any other board. I got one once and it was a debugging nightmare until I realized the CPU was intentionally bricked by DELL...
This seems like a very brilliant and almost obvious idea, is there a reason why this method wasn't a thing before? Besides the PCIe bandwidth and storage speed requirements.