My large iCloud movie library hasn't loaded on my Apple devices (MacOS, iOS, tvOS, iPadOS) since the Apple TV app was released.
I've created multiple tickets. Some of which have been escalated to engineering but I have never had any help fixing the problem. I've noticed that on non-native Apple TV apps (like the Apple TV for Samsung Smart TVs or Roku) my very large movie and tv library shows up. Also, when family members on my iCloud family try switch to view my library, they can sometimes eventually (after hours of spinning) view my library. But that is only temporary and goes away when they switch back to their own library or close the app. It is very frustrating because I've invested so much money in Apples iTune Store content and, although I can still watch what I've purchased if I search directly for it, I can't browse through my collection or create playlist and its not a very good experience.
This started happening when Catalina was released and iTunes was replaced by the Music App and the Apple TV app. It seems like it just times out so it doesn't wait for the library to load. And, as I stated in the title, it's not just on MacOS. It happens on every Apple device. iOS, iPadOS, MacOS, tVOS. I always keep them all updated to the latest versions and I even pay for the developer licenses so that I can try out the betas to see if it gets fixed. This is been happening for years.
MacBook Air 13″