Digital files purchased and downloaded from iTunes are protected by FairPlay DRM technology, if you would like to play them via Sonos app, you need to use DRM Audio Converter for Windows to unlock this limitation and convert iTunes audio files to Sonos compatible audio format. And then you will freely listen to iTunes files on Sonos.
Sonos Connect has very high jitter to be feeding to a DAC:
Synchro-Mesh can reduce this to 7psec, lower than ANY CD transport. You want Sonos to sound better than a CD player? The Synchro-Mesh can do this.
Apple Music Converter Mac is the tool for me to convert purchased iTunes music from M4P to MP3. Since all Apple music are encrypted with fairplay DRM protection, it can be played on Apple devices only. Fortunately, now you can use this DRM removal tool to remove DRM protection and convert music to MP3, WAV, FLAC, M4A, M4B, AAC, etc at faster speed without hampering the quality. After conversion, it will be much easier for you to play all Apple music on any devices freely.