For example,i think the the original piano sound in the mod doesn't sound very good.If i can use VSTi plugins I've downloaded in place of its original, less impressive sound, should definitely result in a better feeling.
Alternatively, can you enhance your music by adding additional and superior sounds in the form of data packs.？As far as I know, Redstone music players usually uses data packs to introduce a wider range of tones to the note block.

Sounds can be freely changed with resource packs, and the repo contains scripts to auto generate pitches

https://github.com/Luke100000/ImmersiveMelodies/tree/1.20.1/common/src/main/resources/assets/immersive_melodies/sounds/instruments

https://github.com/Luke100000/ImmersiveMelodies/tree/1.20.1/scripts