I thought of doing what Jeff did here but then I realized that I do want more:
- I would like to transcode properly some 4k heavy footage
- being able to have proper HDR support
- I don’t mind it being a fully *arr
device on top of also a TV box, hence I’ll probably skip LibreELEC altogether in favor of NixOS + Kodi to have a 1-file config to be able to have it reproducible quickly 
- I also checked the support of the different devices from LibreELEC with the rabbit hole of Rockchips + Allwinner and which SBC to pair it with, best contender was something like a BananaPi BPI-M7 but then I understood that the price, features and architecture wasn’t for me, I’ll rather stick to x86
- hence no more LibreELEC for me, too restrictive, I need more and more flexible too (being able to have potential plugins for YT streaming, Moonlight some games on it, have eARC working)
TLDR: I’ll probably grab myself a MiniPC that matches a good ratio of Intel’s Quick Sync Video so that I could have the best of all worlds. 
Currently not my prio tho but I might circle back this this topic later this year to fully get rid of my AppleTV.
In the meantime, OP here went quite on that small SBC journey themselves apparently, give it a read maybe.