It can be annoying when games don't have a separate volume control for the music, as I've noticed. Here are some possible fixes if you're having this problem:
Verify the settings: To make sure you didn't overlook any audio settings, double-check the game settings. Options can occasionally be concealed inside submenus.
System Volume Mixer: To change the game's audio without affecting other apps, use the volume mixer on your device.
Community Mods: Search for patches or mods made by other players that include volume control choices.
Get in touch with the developers: Suggest including this feature in upcoming updates by getting in touch with the game's support staff.
With luck, one of these will be able to assist.