Apple Music Error 54 - Files on NAS

I recently upgraded my mac to a new macbook air using the Apple migration feature. Everything seemed fine until i get to Apple Music. My old machine stored Apple Music files on a NAS and this worked happily. I have been able to access my library (20,000+ songs) successfully on my new Macbook, but Apple Music won't let me add to the library or consolidate the library. Doing so results in an error 54.

So reading many similar posts, I thought I would just move the library to my Macbook Air physically and be done with it. My process was, to:

1. Change location in the Apple Music settings. This initially results in the file location for new files on the Macbook, but the song files for my library are still on my NAS.
2. Consolidate files (hopefully bring all the music from the NAS to the Macbook Air).

This unfortunately still results in error 54 when I try to consolidate.

I have checked the permissions and I have read and write access (but the 'get info' screen describes it as 'custom access'. I tried ensuring that the NAS user is in the admin group and also gave guest permissions to the NAS share where the music resides. Still no luck.

I want to keep my star ratings, playlists, metadata and album art as a lot of work has gone into getting them into a good state.

Additional piece of info - my old machine is no longer available.

I would be grateful for any assistance to please help me to either:

a. Give my Apple Music proper access to my NAS files, or

b. Allow me to consolidate the files on the Mac without losing the ratings and metadata etc.

Cheers

Ken