Although I’ve seen conflicting info on this over the years, most of the older Sonos devices are only capable of handling 44/16 streams, although Sonos advertises that its devices will handle up to 48/24 without openly disclosing which ones actually are limited to a 44/16 max.
Roon appears to use the default of 48/24 for all Sonos devices, so as @Michael_Harris indicated, one can (should imo) reduce the Max bits per sample (PCM) in Device setup to 16, especially on older devices, and even consider doing so on newer devices if you’re still having issues with dropouts and stuttering. The difference in size between 16 and 24-bit streams/files is not insignificant.
I did this on all 9 of my Sonos devices when I first started using Roon a few months ago, and it immediately stabilized my system. If that hadn’t worked, I wouldn’t be here today making these comments. In fact, I believe my Sonos system is more stable by running it this way than by using it standalone with the Sonos controller app.