I’ve purchased a few HP Elitedesk 800 G3 Minis (refurbished) for about $125 on Amazon. They even come with Windows 10 if you’re looking for that. They’re a deal considering the Pi’s extra expenses like power, case, storage, etc.
The Dell wyse 5070 idles close to 3-5 watts. A bit more than the pi, but pretty close. It's older now, can be picked up cheaper than a pi off eBay. DDR 4, sata m.2, on board emmc flash. M.2 a-key for WiFi. Max 16GB ram.
When you throw in m.2, lots of ram, all that IO eats power. So the minimum idle power creeps up. Arm boards too.
There is also a general improvement in code support by sticking with x86. I bought a similar 10 year old i5 based workstation dell and so many little things just work _better_. I didn't realize just how much of my battles were based on hardware architecture issues.
I love the principle of the mini elitedesks, but some have a terribly annoying fan. It's not firmly attached to the chassis, so it rattles while spinning (and it spins all the time). The heatsink uses a proprietary 3 point attachment, so you can't use a big aftermarket cooler instead (even though it wouldn't fit in the case, I would have accepted the compromise).
Not sure about the <=G3 and >=G7, but the G4 and G5 have the issue. The G6 seems to have the fan attached more firmly, but I've never tested one in a quiet room.
Hp Elitedesk and prodesk are the two 1L available models they have you want to hunt for.
Lenovo has M700, M75q (AMD) and a bunch others ranging from thin client to workstation performance.
Generally new ones are awesome at about $700 but older ones are absolutely capable for upgrading ram, disk, wifi whatever. there are modules for up to 10g and other things too. Servethehome on YouTube has a bunch of guides.
I did something similar too, just beware of refurbishers putting cheap/trash SSD disks in those machine, they can stop working all of a sudden sooner than later (I experienced that on my skin)
