I use my religion to hide the fact that I'm listening to anime music
Why would you hide behind religion for liking anime music?
I don't want people to know I'm an anime fan.
I don't think is is against any religion to like anime music. Many people enjoy listening to music featured in anime.
I'm going to listen to it on spotify in volume under 50%.
Don't hide who you really are. I'm sure people won't care that you like anime music.