That is interesting information. Yes, there always is more to the story.
Having said that, at the end of the day, and as a user without deep technical knowledge, my experience is such that I am trying to stream from my Plex server and I’m not getting Atmos. The Nvidia shield can do it, but I don’t want to buy another streaming box just for one individual source. The Apple is better for all the commercial streaming services and is a very user-friendly interface. I’d prefer to just keep the one.
As you have found out, Apple TV does not support decoding Atmos by pass through to another device.
As far as I'm concerned Apple TV is a bust and I would never use it.
I personally use HTPCs for streaming, but I use the App on my LG TV that supports the BPO app, and that is really the only Atmos Stream that I grab. Windows does not support Atmos from some sites, but it does some.
So for Atmos I just use disc and the BPO app. I think the number of good Atmos streams are far and few between.
I have a pretty severe antipathy to those stand alone streamers and don't use any. So I can grab a lot of streams that no streamer could grab.
I use a DIY HTPC built round a gamer board for my HTPC room.
In our great room I had an Intel Nook for the last few years, and swapped it for this
Beelink Unit to get ready for the end of Windows 11 a couple of weeks ago.
That unit is superb value and far more use than any streamer.
It comes loaded with Windows 12 making it even better value. Better hurry though, as Trump will make them unavailable if he already has.