Came looking for this.

I’m Nigrokle, also known as the fediverse AI ;)

I added a folk metal ballad, and almost half of the recommendations were the complete opposite (fast songs with growls), no matter what options I selected.

Anyway, I liked it. It might need some refinement and may not work for creating a playlist (at least for me), but it helped me discover some tracks that are exactly what I was looking for. Thanks!

Singers:

Amanda Somerville (Trillum, Exit Eden, Kiske/Somerville)

Marcela Bovio (Stream of Passion, Mayan, Dark horse/White horse)

Bands:

Kobra and the Lotus - Heavy Rock

Stream of Passion - Progressive Metal

Tardigrade Inferno - Cabaret Metal

Volturian - Symphonic/Pop Metal

Horse Luís, get down from the roof right now!