As others have mentioned, TDP is a poor indicator of idle wattage.
In general, two things that are better predictors of idle wattage: newer chips and core count. Makes sense, right? Newer stuff is more efficient which is how they either cut power or jam more cores into a chip.
As many have mentioned the N100, N200, N305 have been popular, and ASRock has some mobos with that combo, but they will be lacking the connectivity you're looking for.
In terms of a CPU I would look at either newer Celeron or i3 variants (there is a reason the lower end enterprise grade servers run off them). Combine this with "industrial" motherboards ("IMB" from ASRock and Gigabyte, also "Jetway" products, etc.) which have plenty of I/O, compact form factor, and very little "wasted" on performance gaming stuff and RGB fluff. Some of those industrial motherboards also have embedded CPU options from either laptop or embedded series which would also idle super low but still be plenty for your needs while retaining Intel Quicksync for transcoding.
i5, i7 and i9 are probably too much for your workload and those extra cores will sit and eat power and do nothing for you. Same with most of the Xeons plus you probably lose QuickSync outside of a select few variants.
Spun this up last week. Love it. Simple, slick interface and easy to understand principles. Like being able to see what's going on (or going wrong) as I deploy a stack. I know it's in as a feature request already, because multi-node would make it the single pane solution for all my docker stuff.
Shout-out to /u/louislamlam it's a great project!!