I'm still running an 8th gen HP micro server, but I would run something else if I could get >=8GB memory and 4 SATA ports for relatively cheap. I haven't seen anything that gets me there yet though.
I planned on buying NVMe extension cable, cut a slit in case, run the cable outsidde, plug in NVMe to 6xSATA adapter outside of the case and keep the SSD's outside, this would need reliable external power supply for SSD (Amazon sells them for ~$30, but I don't trust them).
I believe you will get to ~10-15w with this setup, at which rate you could build regular ITX/MATX case to hold all SSD's with i3-10100 and be at ~16w idle.
[0] - https://www.u-nas.com/xcart/cart.php?target=product&product_...
Built-in virtualization and docker. It's $500 at Newegg.
https://www.synology.com/en-us/products/DS420+#specs
They make bigger ones, of course.
On the other hand, I'd wager you can look at what chipsets they chose, and cobble the same thing together for less (maybe even with 8gb).
I decided I didn't want my data backup to be a hobby, so I hold my nose and use their stuff.
It's fine, and it has some nice stuff like let's encrypt reverse https proxies, it emails every time the power or network drops, etc, etc.