I don’t believe the Tidal app on the Samsung TV supports Atmos.

To get Atmos through Tidal you would need to use an external media device such as the Apple TV 4K, Fire Stick/Cube or Nvidia Shield etc.

And what about the Service Tidal on Sonos App? When I use on that service, the Sonos App dont say anything about the codec in use, checking on the About section also, but bcuz I can change the Soundround option (ambient or full) I´m sure, Atmos is not working… 

I was hopping with the service Tidal, direct on the Sonos ARC will work OK, bcuz the TV is out off the “road”, right? 

I´m also asking direct to Tidal and Samsung about this issue…

Please, forgive me for my english… Im from Argentina… 

Regards!!

Your English is better than my Argentinian!

You will not get Atmos using Tidal within the Sonos app directly.

Only Amazon Music Unlimited will play Atmos using the Sonos app, however Amazon Music on Sonos is not available in Argentina.

Thank Mr T!!! Im proud about my english now lol….
Ok, last one… if you can help…

I´m also asking with the brands Sagemcom, Samsung and Tidal about this: 

This TV-Box is available on my country… 

Sagemcom - Model: Modelo: VSB3918 - OS: Android TV 11

Bcus is an Android TV device with OS Version 11… maybe this is a good device to use the Dolby Atmos content on Tidal  with the App form the GooglePlay Store. 

The device isnt cheap.. so Im just trying to check before buying...

Thank you very much again for your help!

Regards!!

Sorry, I do not know if the Sagemcom box will give you Atmos with Tidal.

Ok, no problem! Thank you soo much for all your help… I´ve to wait for Tidal, Samsung and Sagemcom replies…
You was really fast!! Thanks again!!
I´ll post any news or test from my side, maybe this can help other too.

Regards!!

I doubt I will get a positive response from Tidal or Samsung. Evidently for Tidal's compatibility with Atmos my TV is obsolete.... 
I'll end up buying the Fire Stick TV 4K, because it is the cheapest offiicial device compatible with Atmos on Tidal. I'm only looking for that, the rest works perfect with the TV and the Sonos ARC.