So, I have been testing streaming from my PS5 (Plex, Prime, YouTube, Spotify) and it looks like everything I stream from the PS5 through the soundbar it's giving me Dolby Atmos (that's what the app is showing). 
 

Not sure who is making the trick because for YouTube I was surprise, I wasn't expecting getting the Dolby Atmos message in the Sonos App. 
 

I tested the same video from Amazon Prime with the PS5 I get Dolby Atmos even tho the movie doesn't have it!! With the NVIDIA Shield I get sorround 5.1 as expected. So, who is making the tick here, the PS5 or the Sonos App is having some kind of bug? But I can notice the sound difference so not sure what the hell is the PS5 doing to convert everything to Dolby Atmos.