Hi new user here - apologies if this has been answered elsewhere, I haven't found it in the forums.

Is it possible to add missing metadata automatically?

A few years ago I ripped all my music to iTunes Lossless (ALAC) format. Unfortunately I got rid of most of the CDs. Now I realize what a mistake this was and I'm trying to fix the mess. I would like to use an MPD player but it requires ID3 tags that are missing from the ALAC files.

In PerfectTunes I can edit sort tags manually but this would take years. I also tried using Audio Converter to convert some ALAC files to FLAC, but this didn't add the missing metadata, specifically id3-tags albumartist, artistsort, & albumartistsort are absent and the player I'm trying to use requires these tags.

Basically I'd like to end up with a library of lossless music files (ideally FLAC) that have standardized metadata that's widely compatible, not limited to iTunes / Apple Music.

Thanks for any tips / suggestions on how to approach this.