Today Apple released iOS 15.6 to the public. The update, while not loaded with a lot of user-facing features, comes bundled with a decent helping of bug fixes and security update.
iOS 15.6 also addresses the issue with the Music app reappearing in its default location in the Dock, kicking out whatever app was in that position. People automatically assumed that this was Apple doing something malicious to promote Apple Music, but it was just a bug. This bug, among several others, has been fixed in iOS 15.6
If you’re already running the iOS 15.6 RC version 2, you can rest easy knowing that it and the publicly-released version are identical.