When you say not populating, you mean this area of the app is empty even though you have services enabled?

The music services I like to use are working okay here in all the Sonos Apps and include..

• Amazon Music
• Apple Music
• YouTube Music
• Spotify
• Sonos Radio
• BBC Sounds
• Plex
• iBroadcast

etc…

I’ve noticed that new releases of the app are not necessarily auto-updated under iOS and iPadOS. That’s an Apple thing, not a Sonos thing. ¯\_(ツ)_/¯

As a first (and easy) debugging step, folks should verify that they are indeed running the latest version of the app. Gear Icon > Your System > Manage > About Your System > Build … and compare against the release notes here

https://support.sonos.com/en-us/article/release-notes-for-sonos-software-updates