Hello Steve,
After adding the needed capabilities to your project, NSPersistentCloudKitContainer manages the notification configuration to keep your App (local storage) updated with the CloudKit storage. Here - https://developer.apple.com/documentation/coredata/mirroring_a_core_data_store_with_cloudkit/setting_up_core_data_with_cloudkit you can see the steps to enable the capabilities so your NSPersistentCloudKitContainer can keep your local data updated.
Now, keep in mind that the freshness of the data from a Public database is different than from a Private database, NSPersistentCloudKitContainer polls for changes on Application Launch and every 30 minutes, see more detail in this year's WWDC session Sync a Core Data store with the CloudKit public database - min 10:30 - https://developer.apple.com/videos/play/wwdc2020/10650/?t=630.
Good luck and feel free to reach out.