Most folks in this situation have used a simple HDMI ‘switch’ with an optical output on it. 

I guess it varies by projector make/model (and it’s available audio-out ports), but there are a few who also seem to setup their projector using the more expensive extractors that support Dolby Atmos audio, such as the Feintech VAX04101A or HDFury Arcana, as per the example shown in this image…

@Lanzeep

Ah I’ve just realised you were referring to the Sonos Ray, whereas my post was referring to the Sonos Arc - so please ignore the above as the Ray does not support Atmos - that’ll teach me to read the title of the post, aswell as the main body of the post. So any cheap audio-extractor/switch that supports Dolby Digital 5.1 and has optical-out should work for you.