> I should be running one of those $300 mini PCs at <20W.

Yes. They're basically laptop chips at this point. The thermals are worse but the chips are perfectly modern and can handle reasonably large workloads. I've got an 8 core Ryzen 7 with Radeon 780 Graphics and 96GB of DDR5. Outside of AAA gaming this thing is absolutely fine.

The power draw is a huge win for me. It's like 6W at idle. I live remotely so grid power is somewhat unreliable and saving watts when using solar batteries extends their lifetime massively. I'm thrilled with them.