If you have no local music and no physical music media, you are pretty much out of luck.

I mean, when you subscribe to services you understand there is the possibility that the service might go unavailable at some point. Some times it's just temporary, but others are permanent (like Google Stadia).

I make a habit out of not relying on streaming services. If I really like something, music or video, I buy the physical disk.

Sorry, I don't have an answer or solution for you.

I rip my physical media and put it on my Jellyfin server, so I can stream it where ever I am.

Just pirate music since I have a subscription and am entitled to listen to music?

Yup.
You can get DRM-Free music from Bandcamp and I know some artists also offer DRM-Free purchases on their Merch Stores if you'd rather properly buy your music.

Depending on which model you have, you may be able to play via bluetooth, AUX line-in, optical in, or AirPlay.

If you want to drop Sonos entirely, there's still a market for even their S1 line of products. eBay time!

I'd like to piggyback on this as I inherited tons of S1 gear (4 Amps, 6 Connects) from a client years ago that I'm considering installing when I move...

The big selling point for me is its ability to seamlessly group zones together. For anyone who has achieved that without Sonos, what are you using? I need 2 (or more) sources that can be played at the same time in different zones and I absolutely do not want volume controls on the wall.

[Edit] I also love having my local and streaming sources in the same app as my zone selection

I used to buy used CDs and rip them myself. So I have my own collection. But to discover new music and listen to things I may not wish to own, streaming is the best option.

The solution? A plex server with a music library that points to your own collection. Then get a Tidal subscription through Plex. You then add Tidal music to your own library as if you were downloading or ripping it yourself. Listen with plexamp on a phone connected via bluetooth, or just use plex client on your shield, roku, firestick, etc.

Now you can listen to things both locally and streamed seamlessly. You can do artist radio to discover new music and manage smart playlists on the plex server itself.

It’s working for me now. I guess it’s been a full day so they’d better be back up. I didn’t notice an outage yesterday but was not around most of the day to listen to music

I’ll also second the poster who suggested streaming an alternate way. I find the Spotify app a more convenient way to stream over Sonos than the Sonos app, and that might have worked.

Yes, I still keep a huge library of MP3/FLAC for music, and play it through my PC which has a full 5.1 stereo setup, or with Jellyfin if I want it in the living room on the home theater setup. I had Spotify and Slacker subs many years ago but ran into too many situations where I couldn't use them and gave up on streaming music.

I use yt-dlp or Lidarr to acquire new stuff these days if the artist doesn't have a direct sale method (if they do, I buy it there). And I don't feel an ounce of guilt. Part of this is because most of the music I listen to is really old, but the other part is because the artists receive almost nothing when you buy their music from the labels. I'm talking a few pennies on a $15 purchase. Go to a single one of their concerts and they'll receive far more of your money than they ever would if you bought their entire discography.

I considered a Sonos system years ago but added them to my mental blacklist when they started bricking people's equipment remotely.

I use a smb share in docker and this same share is connected with bonob.

Bonob is in Sonos App (but in the s2 app you could also add the sms share)

For PC Listening I use Navidrome (same share) and for mobile I use subsonic streamer with offline access to same share / navidrome.

I use my Roon sever to stream and group mine. Expensive to get into, but smooth enough to get partner approval for use.