How do I access my iTunes music files from an iMac running Monterey V12.7.4 with the new Sonos app/system?

The simplest way is to not use the app directly as its glitchy in the queue system and does not intuitively load random songs. Go to iTunes, select random tunes via albums (not songs) and then click bottom circle icon that symbolises ‘Airplay’, selecting your speaker set up you will succeed in playing your music! This is a work around to a crap app presently where the programmers don’t seem to know the on the ground nuances of peoples systems in GB, security wise, or app wise or whatever!? From what I see, the music channel is interfering with Sonos ARC HDMI TV channels and surround Play 1’s and / or Alexa is buggering up the sytem too?! Oh, if yo have a Macbook Pro, you can over-ride the new app with S2 but you have to do this EACH TIME!

Unfortunately, only half of my 12 speakers are airplay capable. I spent 3 ½ hours on a call with a Sonos tech. He tried everything he could think of to get me access to my 40K+ songs that are on my iMac. Songs that are original recordings and songs from old artists and albums that are not available on any streaming service. The tech couldn’t figure it out and told me to copy all my songs to a NAS drive and play them from there. The problem is, I have almost 100 playlists of music I will lose if I do that. Sonos really crapped the bed on this one. I’m so disappointed with this company. 

Sounds like you have problems. Sorry I can’t help. It works for me but in a roundabout way which is VERY annoying- good luck! I ve seen some on here debug new app on ALL systems and then load S2 but that’s radical and risky for you!?