Found another thread about it.  It’s on tidal apparently to get it sorted

unfortunately, we cannot yet stream Atmos from Tidal to Sonos.

Happen to have the thread in your history you could share?

Has Sonos said it's on Tidal?

Any updates on this? I’m looking forward to being able to listen Dolby Atmos music in my Sonos speakers.

Same issue, but when I use the Tidal app on the television it shows in the Sonos app as Dolby Atmos.

The Tidal app on your TV can send music over a high-speed HDMI cable to your Sonos soundbar in whatever format it sees fit - in this case, Dolby Atmos.

But the Tidal music service on the Sonos app is not currently able to get your speakers to retrieve Dolby Atmos from Tidal over wifi. I’m sure this will come, like it did with Apple Music and Qobuz.

(Another example is the Apple Music app on Apple TV was able to send Lossless music to the Sonos Arc well before Apple Music on the Sonos app was able to send Lossless to the Sonos speakers.)

Thanks,I had Apple music but it wasn't working on Sonos anymore so I'm trying Tidal .

Hope these people taking my money, can get this mess sorted.

Or I'm afraid goodbye Sonos.

I’d imagine with time Sonos will be able to play Tidal’s Dolby Atmos tracks within the music service on the app. The addition of Apple Music Lossless compatibility was a massive surprise to everyone when it arrived in May, so you never know when Tidal and Sonos will sort things - I’ve no doubt at all they will be in discussions, as it benefits both parties.

You’ll need to play via the TV for now of course…

Or try Amazon Music?

I found that if you play the Dolby Atmos content within the Tidal app then use AirPlay to send to Sonos speaker it appears to work - only AirPlay not Sonos.

Are you using ios18? There is news that Apple is bringing some sorts of spatial audio to airplay in ios18 but there is no exact details that with which devices it works

“Spatial Audio over AirPlay with iOS 18”