You're right kkk but releasing on Steam would bring more people to play :)
Um that seems like an easy problem. Most VNs use free music and I never once quit a VN because the music was bad. Worst case i tone the volume down.
It's especially weird as you have SO MANY illustrations, you probably have thousands of euros worth of art. Even if you had to spend 50 euros on some music it would be worth it.
I'd be more worried about how much you pay your english editor. I quit many VNs because of a bad translation.