There is no need to add a MusicKit Capability in Xcode. You only have to provide a NSAppleMusicUsageDescription in your Info.plist.

I use https://github.com/ggruen/CloudKitSyncMonitor for a similar use case and it works quite well for me.

I am not sure I exactly understood your problem. However why are you not using a background refresh of an app that fetches and uploads that data to your server. In that case you can use MusicKit and have nothing to do with tokens. Am I missing something here?

Have you tried the .onOpenURL modifier? This works for me

I finally figured this out. It's really weird but I found the issue. In the initializer of the TimelineProvider struct of the UpNextWidget(), I created a SwiftData modelContainer. Once I remove that from the initializer to the function that will need the ModelContext, it works reliably as expected. Obviously this can not be intended behavior. I filed a feedback with a sample project based on the template for Live Activities that illustrates the problem. FB17655658

My request took around 4 weeks to be approved.

It is best to submit these through https://feedbackassistant.apple.com

You can pass --enable-icon-stack-fallback-generation=disabled as a flag to the asset catalog compiler. Go to project -> Your target -> Build Settings -> Search for "Asset Catalog" -> Add the mentioned flag in Asset Catalog Other Flags. In this case versions prior to 26 will continue to use the previous app icons. However for my project this caused problems when uploading to App Store Connect apparently due to missing png icon files. This has never been a problem before and the app seems to be displayed with the correct app icons at all times. I am also using alternative app icons. I am yet to further investigate this to file a good feedback report.

I tried this a while back with no success so I filed FB17995050