Samsung Q90r with Sonos Arc hdmi hdcp 2.2 switch box

I’m afraid this won’t work. You cannot get Atmos over optical even with the HDMI adaptor and your tv does not have earc. HD fury are currently working on a device that will allow this to happen and Samsung claim they are working on an earc update for 2019 tvs. If that did happen then you could get an HDMI splitter, check their site and the arcana for more details or with earc the tv should do this job for you and solve lip sync problems 

Thanks for your reply but please would you look at my diagram ( regarding your mentioning Dolby Atmos and optical )

Using my proposed set-up for the Arc my Samsung TV is not using optical but is using HDMI from its Arc HDMI port. 
Both SkyQ and Blu-ray are using optical but that is fine as I only intend to use the TV’s native Apps for Dolby Atmos. 

As I understand it the TV Arc port will support compressed Dolby Atmos as provided by the Apps whereas eArc is only needed for full-blown Dolby Atmos for the currently limited number of 4K Blu-ray releases
My original question really only relates to the proposed use of an HDMI switch box to avoid having to go round the back of the TV and physically unplug the Sonos optical/HDMI adapter cable and insert the TV ArcHDMI cable into the Arc Soundbar when I want sound direct into the Soundbar from the TV. I just want to know if a regular HDMI hdcp switch box would work with an HDMI arc cable

if my Samsung TV didn’t delay the SKY/Blu-ray audio pass through I wouldn’t need this sort of messy set-up :-( 

 

Ah sorry when you said you were looking at buying the arc for it’s Atmos I assumed you want want it from sky and blu ray; no arc cannot be passed through using a switch box, the arc handshake has to be direct between the Sonos arc and the tv from my understanding. As I say HDfury seem to be a few months from solving this problem and allowing you to use your blu ray and sky box for Atmos as well in the arcane or whatever they call it; I would wait until it has been tested and proven though rather than buying an arc in the hope it works 

Thanks. I have recently bought the Samsung Q90r ( last year’s top 55”Qled ) against my other choice LG’s similarly priced OLED. 

I chose the QLED set because there is no fear of screen burn and the QLED set is nearly as good a picture as the OLED set. 
 
Having read many reviews I still missed the fact that people were reporting lip-sync errors when passing through 5.1 Dolby Digital. The video is ahead of the audio so SKY and Blu-ray need feeding directly into my Sonos Beam using optical cables. At present I use a 3 way optical switch to feed all signals including TV into my Beam with two Ones’ surrounds. 
 

This does sound really good but there is just no way so far that I can upgrade to get Atmos using the Arc. I’m surprised that Sonos didn’t ditch the simplicity of having just one port with this more complex Soundbar. 
It’s also surprising that professional reviewers to the best of my knowledge never check out how the TVs they review handle ancillary equipment that is likely to be used in the real world. 
Thanks again for your input. I’ll look out for updates on HDFury.