Hi there, I have build a nice backup NAS recently:

Supermicro X11SCL-IF 16 GB ECC RAM 2666 Intel i3 9100T M.2 512 GB System Disk 4x 8TB Ironwolf 5400 RPM Fractal Node 304 Case Be quiet Pure Power 11

This is around 40W @the wall with all disks spinning and has Intel quicksync for decoding. My use case is mainly backup, you should consider i5 for hosting more apps on it. The processor was 30$ at eBay but is quite low power and has ECC support without being a Xeon processor. The newer generations of i3 do not have ECC ram from the spec. The board itself was 300€, but wanted ECC ram. The case is well cooled what ist most important for a system running for a long time. You should also consider N100 mini computer in addition to have more flexibility in the long run for different application demands.

Hope this helps for decision making

I've been running an n100 box as my main everything box for about 1.5 years. I capture metrics on it and can say the thing is nowhere near capacity. This box is running jellyfin, a dozen or so nfs mounts that are heavily utilized, a dozen or so lightly used samba mounts, grafana, prometheus, jenkins, and a handful of mysql instances. I maxed out the ram (32gb) from the start and it averages 8gb usage, and has never exceeded 10gb. Historically, the CPU usage averages 28% utilization. I think as long as the board has nvme storage you'll not feel constrained by these little hosts for many years.

First, I think you're attacking this from the wrong angle. You're focused on ECC memory for some reason, but that's not going to prevent bitrot, just potentially reduce errors in transfer, or catch issues. Your filesystem of choice has more to do with degradation in storage.

Second, you haven't mentioned any of the boards and their storage capabilities. Do they support the correct number of drives you want to use? Do they support hot-swap, and is that even something you care about?

Last, you want more services, and but are worried about power consumption...that's not how that works. More services means more CPU and MEM util, which means more power usage. You can either constrain your TDP at that point by using an UNDERpowered CPU and have that tradeoff, or provide a more capable CPU and take an increased TDP. There is no third option, that's just how it works. Pick the more capable CPU and take the power hit (really, it's going to be minor compared to a large server), and just run the things you need to run instead of coming back in a year and wanting to flip it again.

I have a jonsbo n1, do not buy it.

1. Cooling is insufficient. Something about the case layout makes the motherboard area not get enough ventilation and the supplied fan can't cool 5 disks, the chassis holding the disks doesn't allow enough air through.
2. Only room for half-height expansion card.
3. Cable routing is abysmal, with sharp edges.