Two music folders in the iTunes Media folder

Hello,

I have a curious issue on my Mac, my iTunes Media folder is located in the usual place : username>Music>iTunes>iTunesMedia

But it contains two folders : Music (size = 6GB) and Apple Music (size = 66.7GB)

I have an Apple Music subscription.

Problem is that most of the songs in the Apple Music folder are not visible in Music, I can only find them in Apple Music and not in my Library.

When I find the song in Apple Music it is shown that this song is not yet added in my library and not downloaded.

Does somebody know why this song is on my Mac and how I can erase it to reclaim some disk space ?

I don't feel like erasing the complete folder because I think some of them are actually in my library, the Music folder is only 6GB and Music says that it has 31.25 GB of music in the library.

Thanks a lot in advance for your help,

Karo.