One of the last major annoyances for me in Infuse on tvOS is to have to refresh the library first thing after launch.
tvOS 11 offers two new facilities to update the app in the background: Background Fetch and Silent Notifications (See https://developer.apple.com/videos/play/tvos/209/ beggining at 7:45 min)
I would like to suggest supporting these features to keep the library updated in the background, so you get a current library view when you start the app, and to update the top shelf without even starting the app. As a minimum a periodic background fetch will do the job.
A little more sophisticated would be a push notification service which allows you to trigger a library update via an API call from your favorite download manager, so you can get even more immediate updates.
James has previously said that there are issues with background processing because Apple restrict what Is allowed by apps in the App Store. I"m not sure if it is the amount of processor time allowed or the APIs allowed to be used by background processes or some other limit; but until Apple remove the restrictions on background processing, the background processing of the Metadata is unlikely to happen.
May be the update should only focus on finding the new files added, without downloading the poster and information. Then, once we launch Infuse, the app will update the content based on the files found in the background process.