My Music folder is cluttered by unnecessary files

When Apple decided to split up all the media apps in Catalina, they didn't exactly complete the transition IMHO. What you're seeing is the apps renamed and specialized, the libraries renamed and specialized, but all sort of lumped together. One solution that really helped me:

1. make sure you close the TV app
2. create a "TV" folder in your home directory
3. create a "Media" folder in the new TV directory
4. drag all video folders into the new Media folder - Automatically Add to TV, TV Shows, Movies and Home Videos
5. drag the newly-made TV Library into the TV folder
6. launch the TV app with option-click and it will ask you where the library is. Select the TV library file in the TV folder.

I created the same architecture with the <home>/Music folder so that it now contains only the Music Library and the Media folder, under which there's just:

• Apple Music
• Automatically Add to Music
• Downloads-Music
• Music (containing all my purchased content)

I found I could also remove all the "iTunes Library*" files, previous iTunes libraries -- really anything with "iTunes" in the name, once Music was up and running.

Podcasts, Mobile Applications are stored elsewhere now.

Album artwork is no longer stored in the iTunes directory, it's in ~/Library/Containers/com.apple.BKAgentService/Data/Music/_archive/Artwork. But you seem to have a lot of folders under Artwork that are not standard.

One caveat - be careful about moving your music content to an iCloud Drive unless you verify you have a LOT of storage there.

Hope that helps.

Just for clarity: