I've been sticking w/ very compact units, mainly ThinkCentre M series "Tiny" and Dell OptiPlex "Micro" form factor, which are both practically identical in size. Both use a laptop power supply. You can get current versions for many hundreds of dollars or generation(s) old ones for as cheap as $30 USD. My most recent ones were older 3rd & 4th gen i5 & i7 CPUs but they still blow current Raspberry Pi, etc. out of the water, have M.2 for network, etc. & SATA for storage. A Dell I have that's a generation newer than these adds NVMe too. It's hard finding these small PCs that have multiple Ethernet but I just added a gigabit Ethernet M.2 card to the one.

On paper, these look promising, no direct experience. Also on Amazon US/CA.

$170, N100, 16GB LPDDR5, dual 2.5GbE, https://aoostar.com/products/aoostar-n-box-pro-intel-n100-mi...

$210, N100, dual 3.5" SATA, M.2 NVME, dual 2.5GbE, https://aoostar.com/products/aoostar-r1-2bay-nas-intel-n100-...

$250, Ryzen 5700U, https://aoostar.com/products/aoostar-cyber-amd-ryzen-7-5700u...

I love the Odroid H series [0]. cheap, quiet and only like 4w idle draw

0) https://ameridroid.com/products/odroid-h3

I was also looking for a successor to the PC Engines APUs and came across https://teklager.se/en/ that lists some possible alternatives that you might find interesting.

Personally I was looking to build a router so I ended up buying a fanless N100 based mini PC from Aliexpress (e.g.: search term is "N100 firewall appliance") and have been very satisfied with it so far (Proxmox homelab with OPNsense running as a VM).

The N100 is the current thing. It is in a large variety of form factors with a variety of available connectivity options.

N100 sips power while performing as well as a 60w quad core Skylake.