I have more compilation CD’s dan Artist CD’s.
With MusicBrainz i have checkt and set al the music TAG, like album, track, cd, track artiest, album artiest, …
Most compilation CD’s have as album artiest “Various artists”
example, searching for the artist Adele i see her albums, but i do NOT see her tracks in al my compilation CD’s … 
If I look in a Various Artists cd i see the track in bold and the artist name in grey … (so i know plex has seen the music tags and knows the artist for this music track)
So ho to see ALL the artists in Plex that i have tracks on my Plex server ?
So if I ask to Alexa to play radio of Adele i hear all her songs …
