It sounds like you might be looking for one of two things: a specific app called Story Music or a way to download an IPA file (app package) for Apple Music.
When people search for an Apple Music Premium Unlocked IPA, they are typically looking for a modified version of the official app. These unofficial versions claim to provide: Ad-Free Listening: Removing interruptions between songs. apple music ipa
If you have obtained an Apple Music IPA file, you typically need a sideloading tool to install it: It sounds like you might be looking for
: Information for the App Store, including entitlements for system features like Spatial Audio 2. Audio Formats and Distribution apple music ipa