Perhaps see the thread linked below and the links off it:

Currently the only way to get Apple Spatial Audio/Dolby Atmos music to play out of the Sonos Arc is through the Apple Music app on an Apple TV 4K connected to a TV with HDMI eARC or the HDFury Arcana.

Thanks!

so direct using Airplay does not help?

neither using Apple music app on Samsung TV with eArc?

No, if you AirPlay Dolby Atmos music to the Sonos Arc, it will not play as Dolby Atmos.

As far as I know, the Apple Music app on Samsung TV’s doesn’t support Dolby Atmos audio.

Read more here about what devices are supported:
https://support.apple.com/en-us/HT212182