Saving a title is not saving its video
My List remembers the film or series so you can find it again. The backup is text containing those references and checkpoints. Neither is an offline movie file.
Prepare in the viewing app
If your chosen service offers downloads for the title and device, use its own controls. Check storage space, audio, captions and any expiry rules before leaving a reliable connection. Test the downloaded item in that app rather than assuming the poster proves it is ready.
APK and media downloads
An APK installs an Android application. A movie download stores media under the service's terms. Cinema Deck does not provide either a native APK installer or downloadable movie files here. The browser catalogue helps you choose what to watch.
Keep a separate backup of your plans
Copy My List before resetting a device or moving to another browser. That protects the shortlist, not a subscription, licence or downloaded video. Restore the list after the move and use the viewing service for the actual media.