I have a long history of constant radio drop-outs and numerous conversations with Sonos technicians to try and resolve the issues. They usually come up with the same monotonous fixes which involve switching all the Sonos items on and off, unplugging the router, and/ or changing router settings, changing all range of network channels.
Also overtime other equipment has been alleged to be interfering with Sonos ie the Virgin Hub4 (which is now in modem mode and operated through a TP Link router), and the BBC Sounds app, which we have stopped using for the time being. The latest item that is suggested to be interfering with the Sonos system is our Devolo powerline.
Just to add interest the Sonos Roam has stopped connecting with the system, although according to the Sonos App it is playing properly.
Reading about similar issues and the lack of solutions, it seems that Sonos is just no longer fit for purpose.
My system is:
Room 1 Home cinema system consisting of Playbar, two x Play 3 and Sub-mini;
Room2: Play1; Room 3: Play 1; Room 4; Port and record deck; Roam