The beamer can be connected wirelessly via Bluetooth. I have connected my old stereo system this way and it is easily sufficient for streaming films. It's not enough for Bluray 4k, but you can save the "extra loop" via the projector anyway and it's better to connect the player directly anyway.
Sonos audio via WLAN is Sonos-specific and I know of neither a beamer nor a TV that can do this. If there is a Sonos audio bridge to WLAN, then the beamer also has HDMI ARC and optical for a digital feed and hopefully the quality question would then become superfluous ;-) But I don't know whether Sonos can also use these standards... (besides PCM, Dolby, DTS and so on should be mentioned). Otherwise, you can also set the digital outputs to PCM. With PCM, however, you are probably not far away from Bluetooth in terms of quality.