This is exactly what I've done, by the way. Same mITX motherboard you cite below with a Ryzen without integrated graphics (since the board itself supports VGA).

This is exactly what I've done, by the way. Same mITX motherboard you cite below with a Ryzen without integrated graphics (since the board itself supports VGA). 10 GbE and a whole bunch of SATA lanes. I didn't bother with trying to get it into a real chassis. I just grabbed a desktop case from Fractal Design that can hold 10 disks and it fits fine in my wall-mounted entertainment center cabinet below my television. It's in there with my router, a switch, and a few Minisforum small form factor Ryzen PCs. The only "gotcha" with cooling is you need to use a CPU cooler meant for Intel even though the chip is Ryzen, but the board documentation clearly tells you this. I'm just using simple Noctua low-profile fans. I also cut some holes in the cabinet and put in USB-powered cabinet fans, so I can keep the doors closed. So sure, it's DIY and some work, but putting together the NAS itself and putting together the cabinet, including the cooling and wiring, only took one weekend. It consumes more power compared to ARM, but I'm cooling a 4-story house with 18 foot ceilings in Texas anyway, so it's not a noticeable difference.