Well I've done some testing for the last week and came to the conclusion that the sound of the Sonos Arc with a Philips OLED806 is very buggy. Let me describe mine setup...
The Philips TV is connected to a Sonos ARC. For most of mine streaming services I use an Apple TV. I prefer this user interface and the smoothness instead of the built in Android apps. I've noticed that the standard setting for eARC on this television is off. But to get Dolby Atmos on the Apple TV this has to be switched to AUTO. Also the sound output is set to 'Multichannel (bypass)'. I have to do this because otherwise I have some lip-sync problems with mine Cable decoder (Telenet) and the Sonos Arc.
So far so good. Dolby Atmos is working on the Sonos Arc with the Apple TV, Xbox,... and there are no lip sync problems at all.
However after a while you just can loose the sound on the Sonos Arc. This happens frequently when switching sources. Whatever you do nothing will works. The only thing to get the sound back working is to disable the eARC function or switch to Multichannel. Reenable those will not give you back Dolby Atmos immediately.
Then there is another issue. On the Apple TV everything is working perfectly with Dolby Atmos (Disney, Apple TV+). Except Netflix...This will only produce a ticking sound. Very weird. You can see a video here (don't forget to enable the sound):
I don't know exactly what is causing the problem but I think the communication between the Sonos Arc and the Philips OLED806 is not faultless with eARC enabled.
