Who's the Tidal > Atmos Expert?
 

Here's what I have:

iphone8 with the Tidal App, mconnectLite, & iOS 13.5.1 - According to Apple, this phone is Atmos compatible with this iOS

Integra DHC-80.6 - Atmos compatible but No Tidal App that I can find. I can stream directly to the 80.6 but cannot stream Atmos music content.

Sony XBR75X900E with the latest Android OS and the Tidal App. I can't for say whether or not this set is Atmos compatible, but the latest Android OS looks to have added it. I can stream directly to the TV and from the TV to the 80.6 via HDMI ARC but no Atmos.

Oppo UDP-205 - No Tidal App, obviously. I can stream directly to the 205 (including MQA files) but cannot stream Atmos content.

Is it that I've simply overlooked something? Surely I don't have four devices as these where I'm just SOL.

Have you tried a Lightning to HDMI connector and run it through the Integra amp?

I am using an Apple TV 4K with HDMI to my Marantz AV8802A and it supports Atmos

Have not tried that.

Any other suggestions? It would be nice not having to have a hard connection to the iPhone.

Get an Apple TV 4K and download the TIDAL app on the device.

Nvidia Shield 2019 also does ATMOS with the TIDAL app.