Ah, I see. It’s the intermediate transfer format between Roon and Sonos which concerns you, rather than direct streaming from online service to Sonos player.
Since Roon appear to tweak the interface at their end -- https://help.roonlabs.com/portal/en/kb/articles/sonos says “As new devices reach the market, small adjustments may be needed” -- have you tried approaching them? I see they also say “Sonos devices accept up to 48kHz/16bit audio” so perhaps they and Sonos would need to come to some kind of accommodation to increase the bit depth.