Apple One / Apple ID - need to merge two accounts or migrate data

With Apple One and consolidated billing for multiple Apple services, we need a simple method to merge or migrate two Apple IDs into one whilst preserving purchased music / films / TV shows / apps.

I have an historic Apple ID that I set up for iTunes many years ago and still use for media and another Apple ID that is used for iCloud and email. I have had discussions with apple support and there is not a method to merge or migrate data from one ID to another. The answer (workaround) given was to add the old Apple ID to Family Sharing which does partially solve the problem, but this is not the complete answer, yes I can view a movie that was purchased with the original ID and play a song, but when watching on Apple TV will I get to see the extra features when I logon with the second Apple ID, I suspect not. My family members are also not happy about losing their apple music downloads and playlists, yes we can try and back this up via exporting playlists and re-importing and/or screen grabbing data and re-downloading, but this is time-consuming and potentially could introduce errors.

Please Apple, make this easy for us, allow us to merge or migrate purchases from one Apple ID to another Apple ID when we take out an Apple One subscription.

Apple One sounds awesome, but please Apple, consider your loyal historic customers who have been with you since when iTunes was first released.