You need to install the Resourcepack & Datapack to make it work correctly!
You can download the Resourcepack here: https://modrinth.com/resourcepack/enders-journey-ender-dragon-boss-battle-music-resourcepack
You can use this Resourcepack freely in your Modpack giving credit to this project and the authors Kami Hikari (Main Song) and Kizarys (Victory Song)
You can use this Datapack freely in your Modpack giving credit to this project and the author StAnimaties
The Ender's Journey Ender Dragon Battle Music Resourcepack & Datapack is used in the Ender's Journey Modpack: https://www.curseforge.com/minecraft/modpacks/enders-journey.
Added a new song that is played during the Ender Dragon Boss Fight