Some feedback for you, for what it’s worth… I’ve had a five-zone(+) Sonos system for many years, but rarely use more than one or two zones at a time, especially now, since I converted to Roon last Fall. Still, sometimes I will group two Sonos zones together (garage and kitchen for example, when I may be going back and forth between them).
I will occasionally get a short dropout at the very beginning of Roon playback to Sonos, whether grouped or solo… Usually after 5-10 seconds of play, with a dropout that may last for 5-10 seconds. After that, which only happens probably less than half the time, the music will play flawlessly (for many hours, or until I stop it). You probably already know this, but you shouldn’t touch any buttons (other than maybe volume up-down) on the Sonos gear or in the Sonos app while streaming from Roon.
My Sonos zones are now all Wi-Fi connected (via Netgear Orbi), though this behavior was also observed previously, when they were connected via SonosNet. FYI: My Roon system is based on a Nucleus (Rev.B), with two RAAT (Ethernet) endpoints, plus a direct (USB) connection from the Nucleus to the DAC in my primary listening room’s equipment rack.
I never get any dropouts, delayed playback, pauses, etc. when playing back content to my RAAT endpoints, whether local library or streaming service. Only the minor issue described above – and only when streaming from Roon to Sonos.
If you’re having frequent/chronic problems that are worse than what I’ve described, you may want to reach out to @support for advice, but given that this involves Sonos and wireless connections, I’m not sure how much they may be able to do.
In my case, I’ve now transitioned three Sonos zones, so far, to Roon (RAAT), and have had zero problems with those zones. Hope this was helpful!