Ditto. Same issue. I have spent the last 3 hours trying to figure this out. I don't know enough about all this but when I play Dolby atmos compatible content (jack Ryan season 1 UHD on amazon prime) , the Sonos App shows the Dolby Atmos symbol, which disappears when I play other stuff. So does that mean I'm getting Dolby atmos output?
This is from the Sonos website. It appears you can get Dolby Atmos without eARC working but the Dolby TrueHD codec will not work without eARC. I don't understand the difference, but the soundbar reviews I have read stress the importance of eARC to get the best sound experience.
I'm having the same issue with my 55 Frame and sonos ARC.
You mentioned Jack Ryan and Atmos - is that from the internal amazon app? I tried that as well and only got 5.1 Dobly Digital plus reported on the sonos app. (no atmos icon in prime either).
I have the exact problem with the same devices. Samsung 2020 The Frame TV with Sonos Arc. I have tried resetting the TV and also tried different HDMI cables. Same issues. You can hear the briefly for a split second when you toggle between the TV Speakers and the Sonos Arc in the "Sound Output" settings of the TV, but it does not stay on when eArc is in the Auto setting.
Thanks for posting this. Seems to be a wider issue with a few of the new Samsung TVs. Same issue trying to get a new Frame 75 and Frame 65 working with Sonos ARC. Extremely frustrating. I hope Samsung come back with a firmware update soon 🙏