Make sure your Plex server is configured to ‘prefer local metadata’ (it’s more than just one checkbox). This is only recommended if your embedded tags are very accurate:
Please only reply to this thread with corrections or questions about the information in this How-To article itself. If you want to report a bug or ask a question about Plex and metadata, please post it in the appropriate forum, where it will have the best chance of being seen.
This guide applies to libraries using the "Plex Music" agent only.
Plex essentially has two ways to identify your albums:
Folder/filename structure – If your files don’t have embedded metadata, or it isn’t accurate, o…
https://support.plex.tv/articles/200381093-identifying-music-media-using-embedded-metadata/
For the second issue, make sure this option is enabled:
