How to restore lost Apple Music library

I had an Apple Music Subscription which I cancelled in January. As part of my phones contract I get a free apple music subscription so I enabled this in February.

When I next opened Apple Music my whole library had disappeared, After speaking to customer service on two separate occasions their conclusion was when you unsubscribe they wipe your library from the iCloud!!

However I have multiple devices that have previous versions of my Music Library (packages I believe) saved in `~/Music/Music/Previous Libraries`. However when holding Option while starting Apple Music app and selecting `Select Library` My old library will load in initially but then gets wiped!!! Whats worse is it updates the package too essentially wiping the old library on that version. Luckily I backed all these up first.

So I assume my iCloud Library is syncing and saying "NOPE your library is empty" and wipes them.

I have tried importing this while not connected to the internet and putting them all in a playlist to export/share but then I can't share a playlists while offline!! As soon as I connect iCloud syncs and wipes the library again.

I have also unchecked the sync option in Apple Music App, but for some reason when I chose a previous library it enables it and wipes it.

How do I update the library in my iCloud with a previous library I have saved.

Why are there so many options to Save/Share/Export your library yet this is so difficult.

Thanks.

[Re-Titled by Moderator]