What does the cryptic crossword clue "Unfeeling music genre? Not so much (8)" mean?

The wordplay uses a charade (building blocks). SOUL (synonym="music genre") + LESS (synonym="not so much") = SOULLESS The answer is SOULLESS.

Unfeeling music genre? Not so much (8)

Guardian Cryptic #29393 | 16 Down | 2024-05-27 flower