I don't know what you did to get yours idling that low. My 800 i5-9500t idles at 9w. I took out the flex io module & wifi card, and make sure nvme has "spin down" but still nowhere near that low.
I had some Acer chromeboxes that would do 4.5w easy without any tuning or setup, and they used pretty low end dyal-core i3's from just barely before the i5-9500t. Generally I don't think servethehome finds many tiny mini-pcs below 7w.