Is here a good place to comment? Giving it a go anyway.
Worth noting that basic album art (cover) can also be scanned from the appropriate tags embedded in the music files. That is where most of my art comes from. Then album and artist art can be scraped from online sources or NFO files with the location of the art, or manually set to locally held files.
Having a folder for every artist on the compilation is a CDart addon thing, not out the box Kodi. Kodi will not do anything with such folders.