What don’t I know here?
The emotional effect that different specific types of music can have on a person. And that it’s a somewhat objective chochmah.
It’s poshut that a talented artist can compose or even play music that can make one feel happy, sad, hefker, inspired to teshuvah, rebellious, lewd, and many more.
All without any lyrics.
You’re right that an immoral composer can write uplifting music, it’s just that they often simply express themselves, including and especially regarding their points of spiritual weakness.