Hello am_alinna,
It sounds like you have questions about what happens if you cancel your Apple Music subscription and then resubscribe after some time.
Apple Music allows you to play songs from the iTunes music collection, build a personal library, and sync music across your devices while you're subscribed. If you cancel your subscription feature that requires a subscription, like maintaining a personal library, won't work and may not be saved. If you don't see your personal library after resubscribing, you'll need to manually rebuild it. You can learn how to do that here: Add and download music from Apple Music - Apple Support
Thanks.