I had a similar issue, as I have a lot of personal recordings and uploaded albums not available through Apple Music.  I found that after about an hour, all of my music was searchable.  Apparently the new app automatically triggers a sync with AM, and it takes a while to index,

Now if I can only add SiriusXM as a service.  I created a new account and system to separate my work instance from the rest of the home (other inhabitants kept tweaking my meticulously implemented settings).  Sirius is still connected in the old account, and appears on the service list, but not in the new account.  Go figure.

The new iOS app is a disaster for my primary use case: playing music from a 2 TB and growing digital music collection on a network drive. 

I can still see my NAS-based music library from the new app, but:

• The old alphabetic speed-scroll is gone. So trying to play something at the “Z” end of the alpha list takes a ridiculous amount of scrolling
• Search no longer includes the NAS-based music library, so search is not an option to avoid the endless scrolling
• I can play individual songs from the NAS-based library, but can’t add an entire album to the queue (this is presumably a bug and not a feature)
• As far as I can see, there’s no option to scan my music library to find new music that’s been added

Is there a way to downgrade to the prior version?

Yeah, I didn’t mention the search or alphabet issue -- but that seems to be universal with the update.  It’s annoying not having a quick way to go to a specific letter in the alphabet.  To update with new music, you have to use the Sonos PC app.  That allows you to manage your library and index it.  

If you use the Web App on your device, such as an iPad:   https://play.sonos.com/en-us/web-app can you play albums from your NAS?   If I use the web app I can play albums from my PC’s music library.  (Which only proves it’s an issue with the app - not my library).

I am having problems playing from my NAS too.

Some music plays, some just has a spinning circle than an error and sometimes it plays completely the wrong track.

My wife’s phone still has the old app and everything is fine on hers.

Yep, that’s what I’m seeing.   I do find that I can play individual songs pretty consistently, but adding/playing an album is where it just spins.    Are you having trouble with albums, or both songs and albums?

Also, have you tried the WebApp to navigate to your NAS -- and see if it can play it that way?   Here’s a link to the web app:   https://play.sonos.com/en-us/web-app

I am having problems with songs and albums. I tried the web app but that isn’t much better. What a nightmare, it’s like it’s still in beta.

Web app offers zero usability for personal music libraries. I moved to the new app on iphone that has lost all awareness of my music library. The PC app still has it and functions as before (including ghost tracks added to some folders but thats another story). My android still has my music library front and centre but - in amongst the headphones ads - it will not allow me to make any changes until I update the app, which I will not be doing in case it obliterates access to my library on that platform too.

Not seen any update from Sonos on what they are doing about this. Neither have I seen anywhere any announcement that they are killing NAS music library functions, so it must just be a testing fail. Waiting patiently as ever. Would reallly like the headphones and an arc, but definitely not investing more until I get a satisfactory answer on the music library.

Kinda Wonky before, Really messed up currently.

Before I could control music playing from my Apple Music library, gone.  Only connects to Amazon owned music?  Sup wi-dat!