Actually not specifically looking for copyright but instead the label/organisation. The reason I included the term is because iTunes doesn't write label/publisher/organization only copyright. It includes the publisher as well as the copyright information, sort of extended version of label/organization.
I'm looking for a tagging application which scraps iTunes for tags, yet to find one. I like their format, full release date instead of just year, Release Type (for sorting) etc etc
I tried kid3 with MusicBrainz and it doesn't appear to write the composer tag. Deezer API also writes composer, author tags, haven't found any application scrapping Deezer, Qobuz, Spotify either.
I'll give Picard a go.