Apple has decided to delay the release of the new SharePlay feature in iOS 15. This new feature will be available in a future update of iOS 15 and will not be included in the first public release of iOS 15 iPadOS. 15 tvOS 15 and macOSMonterey.
According to Apple, SharePlay has been disabled in iOS 15 iPadOS 15 tvOS 15 developer beta 6, and will be turned off in the next beta 6 release of macOSMonterey. To allow
developers to continue testing SharePlay integration with their applications in iOS15, Apple is releasing a new SharePlay development profile.

As Apple explains:
SharePlay has been disabled in iOS 15 iPadOS 15 and tvOS 15 developer beta 6 versions and will not be available in the next beta 6 version of macOSMonterey. SharePlay will not be available in the first release this fall. SharePlay can be reused in the developer beta release in the future and will be made publicly available using the late fall software update this year. Teams can install this development profile to continue developing SharePlay support for their app.
We are very pleased with the high level of enthusiasm of the SharePlay developer community. We want to provide users with this so that they can experience the app with friends and family in a completely new way. ..
Thank you how many teams are working hard to build the SharePlay experience and successfully create and receive GroupSessions via the Group Activities API to avoid development outages. We provide a SharePlay development profile that allows you to. Remove the GroupActivities entitlement if the
team plans to send updates to their applications for an initial release of these platforms. We will provide guidance when SharePlay is re-enabled in a future developer beta. At that point, its a good idea to include the GroupActivities entitlement in your code. SharePlay was touted as one of the key features of iOS15 when Apple announced the update at WWDC in June. This feature allows users to sync and watch movies and TV shows via FaceTime, collaborate on Apple Music playlists, or share screens.
Delay means that SharePlay will be available as a subsequent update to iOS15, such as iOS15.1 and iOS15.2. Apple does not provide any additional information on the reason for the delay.
Apple has not yet mentioned whether Universal Control, a key feature of macOS Monterey and iPadOS 15, will be available at launch. This feature was previously unavailable in beta.