How can I create a note-taking app that supports SharePlay?

I would like to create a custom experience using Group Activities. It would be a simple note-taking app in which the users can create a shared note using SharePlay. The tricky part: I would like to save the created note persistently (using CoreData) on all of the user's devices.

Is it possible to save the data on all of the devices using Core Data or any other technology?

How can I create a note-taking app that supports SharePlay?
 
 
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