Hello, very cool you’re posting in SB. The Node 804 is an amazing case. I’ve built a server in it using the Supermicro X8SIL-F, which is the original NAS Killer 1.0. Hard to beat that setup for compactness and density, with being able to install 10 - 3.5" HDD’s and 2 - SSD’s. Very nice!
Have you looked at ordering off USA eBay and shipping via a forwarding service? Some folks living in Europe/Scandinavia have done that successfully. The real problem is when a bit of tech arrives with problems. It’s much more difficult/costly to handle returns/replacements.
What OS do you plan on running? If unRAID, then here’s a hardware compatibility list. Unfortunately the list of specific boards trails off at around 2013, though they admit this and offer general advice. You could also search the unRAID forum to find current boards that others are using.
If you’re planning another OS, then leave more information. I’m sure someone will give you their experiences/advice.