Hello fellow Spaniard! I just checked the prices and they don't make any sense anymore. A few weeks back you could find the board in Aliexpress for 150eur, now it's twice that price or even more. I got mine fom eBay, didn't think of checking Aliexpress at the time. As per the other parts, I got a quite fancy Metalfish PSU [0] (was on sale when I got it), a power button [1] from Ali (not necessarily needed) and an ESP32 [2] for the remote power on. Then a high pressure fan, I went with Arctic P12 Pro [3]. Wifi and BT adapters whatever works on Linux will work.

[0] https://es.aliexpress.com/item/1005009609601844.html

[1] https://es.aliexpress.com/item/1005011847734240.html

[2] https://es.aliexpress.com/item/1005007479144456.html

[3] https://www.amazon.es/dp/B0DJDC74BP?th=1