My Xigmanas based NAS runs off a Supermicro X7SPA-L mainboard I bought used on Ebay; I also built a similar one for relatives of mine with roughly the same conf

My Xigmanas based NAS runs off a Supermicro X7SPA-L mainboard I bought used on Ebay; I also built a similar one for relatives of mine with roughly the same configuration and they both still work flawlessly after years. If you can find a X7SPA-H board, it employs 6 internal SATA ports, though for more ports you can always add a cheap SATA+eSATA PCI-E controller, such as the ASM1062 based one I have on my NAS; they're cheap on Ebay. The CPU's TDP is around 10 to 13 Watt; certainly higher than a Raspberry PI 4, but in the same ballpark and well worth the gain in performance and expandability. Speed is not stellar, still enough for most tasks including serving different HD video files (important: files, not streams) to more Kodi boxes. A future development I want to explore is using one external eSATA box so I can add more drives. I'm not sure however about any incompatibilities between BSD (or Linux) or the PCI-E controller and external SATA port multipliers.