What I'm looking for is 4K HDR playback, and the linked article claims the Mac Mini (2018 or later) is only capable of 1080P HDR playback. Now certainly I can understand resolution/hdr limitations on content that isn't provided by Apple (like HBO from an App), but this is with premium HDR content from Apple.
I have no reason to believe that the article is correct because if it was the Mac Book Air would have the same capabilities/limitations as the Mac Mini because with the 2020 models they're practically the same thing (minus throttling they use on the Air to avoid having a Fan).
Plus HDMI 2.0 is perfectly capable of 4K HDR10@60fps so purely from a technical standpoint there is no reason why the Mac Mini M1 shouldn't be just as capable of 4K HDR playback as the iMac.
I don't see any reason why you'd have to use a Thunderbolt3 port to connect up your HDMI 2.0 (or greater) TV.
I asked this 4K HDR question to the "pre-sales" Apple Bot, and it was thoroughly confused. Haha. Eventually it said it would have to get help, and I haven't heard from it since.
The other thing that's interesting is this Article totally leaves out the Mac Mini M1.
https://support.apple.com/en-us/HT210437#mac
I do expect these articles to get updated to clear up any confusion, but for now they're basically wrong.