Maybe a little late for you, but also look at Dell Optiplex micro form factor. They are not quite as small as the Intel NUC or that Ryzen you referred to, but close. I bought a 3050 recently. Installed a 5 port sata card into the NVMe slot and a 2.5GbE card into the wifi slot (m.2 "a+e" key), and turned it into a low power consumption file server (about 10 W at idle, not including disks).