Music metadata sources

Help me understand metadata sources for music libraries please. I thought Last.fm was deprecated as an agent, but Last.fm data still seems to be populating into my library even though the agent is set to Plex Music. On further reading, it seems that Plex Music is pulling data through from multiple sources, which may include Last.fm? Is that correct? If that is correct, is there any way to block Last.fm as a source? I’m guessing probably not. It’s infuriating due to the rash of copyright text at the end of artist bios (which for lesser-known artists is often longer than the bio) but also for the fact that it inserts paragraph breaks that are interpreted by Plexamp as double-breaks, leaving large gaps between each paragraph.