church music vs musical style

church music and musical style both are nouns.

Word	Noun	Adjective	Verb	Adverb
church music	Yes	No	No	No
musical style	Yes	No	No	No

As nouns, musical style is a hypernym of church music; that is, musical style is a word with a broader meaning than church music:

church music: genre of music composed for performance as part of religious ceremonies
musical style: an expressive style of music

Other hypernyms of church music include music genre, musical genre.

church music (noun)	musical style (noun)
genre of music composed for performance as part of religious ceremonies	an expressive style of music