Hasn't been updated since macOS 10.13 (High Sierra), as such it may be deprecated soon
It still aggregates media from all of the media apps that iTunes was split into (Podcasts, Books, TV, etc). Additionally:
Support is missing for certain item keys
Recent additions to internal playlists aren't included (e.g. Loved playlist)
MediaPlayer has support for extensive library queries and would resolve these issues.
While the relevant classes of MediaPlayer don't natively support macOS, they do support Mac Catalyst 13.0+ (Catalina). Further research should be done to determine whether or not functionality would be adequate given that it isn't a native macOS framework.
Issues with iTunesLibrary:
MediaPlayer has support for extensive library queries and would resolve these issues.
While the relevant classes of MediaPlayer don't natively support macOS, they do support Mac Catalyst 13.0+ (Catalina). Further research should be done to determine whether or not functionality would be adequate given that it isn't a native macOS framework.