Find an identified album with Otmar Suitnar, add it to your library, and you will get the metadata. (You may have to delete/merge your current blank Otmar artist though as depending on how you do it, you may end up with two such artists))
Ah - OK, thank you. Haven’t read that post (because the subject didn’t seem like it fit my question). So I’ll have to go the musicbrainz route to get the album identified because the other “Otmar appearances” are all on unidentified albums here.