Roon can play to any Airplay 2 device from any server its run on nuc or not it doesn’t need an apple device to do it.
I would reboot all your network gear and then speakers and then your server and see if the Sonos streaming returns. But you can use them via Airplay as well. That is one of Roons benefits.
Thanks for writing in - it’s good to see you on the community again!
@CrystalGipsy makes a good point in rebooting your Roon devices and router. I’d also double-check to confirm all your audio devices are on the same network subnet, you can typically check this from the devices list within your router settings.