Seconding the Plex recommendation.
I should have said, I don’t have a PC or space to run one permanently as a server. Ideally it would be NAS or even better cloud based. I’m starting to think I’m asking for too much………..
Soundcloud almost works but rejects some files due to Copyright. Understandable as they probably think I’m trying to share/distribute. In reality I just ant to listen to some old tunes.
There are a few that might work. I have all of my music uploaded to YouTube Music; the interface isn’t great (especially the Sonos integration) but it works, and I can’t really complain since I’m using the free tier. The free version limits streaming to 128kbps but you can upload 100,000 songs and there’s an iOS app in addition to Sonos integration.
iBroadcast also has free and paid tiers and both can play through an app or Sonos.
VOX is a bit slicker than those two; no free tier but unlimited storage and maintains original file quality, and again has both iOS app and Sonos integration.
I run Plex on my QNAP NAS.