IMHO - this has been broken for a long time even with iTunes for many versions back to Sierra and maybe even before that as Apple tried to make thier music streaming work within iTunes along side of the local library files many of us have built up over the years.
There are some Scripts / Plug-Ins at
Doug's Apple Scripts that might be in line with what you are looking for and my understand many have been updated for the "Music App" Big Sur - in addition to the iTunes version
Many of my imported CD's have lost the Artwork and apple no longer provides artwork (Gracenotes Data Base) for many of my CD's - so I usually just go to
All Music or even better
Discogs and grab a good quality image of the artwork and manually add the image in Music (can be done for the album in one shot) - get info
Once this is done manually it seems to embed the Artwork permanently - but I also save the image in the music file folder so I can use the "Show in finder" and quickly repair any lost artwork with the saved image in the future
Both All Music and Discogs are great sites for CD and Vinyl Album info and Artwork