I haven't seen one and in most cases music hacks for non music games will be based on another version of the game (later port, home console version, more powerful device port, original version of the game if this is a later port) or maybe a CD it came with/was released later.
Is the music that bad for you? Very little is anywhere near as iconic as other entries in the series (and even what remixes of that are present are still nothing to write home about) but I don't recall it being bad.
I had a quick scan around some tracks, some play and some top 10 lists of it too just in case I had forgotten. Bit more noise channel than I might go in for were I making it and some of those trended towards clipping but still nothing awful.
If you are on PC you can fiddle with many of the emulators to go beyond what the GBA sound setup offered and possibly boost some things.
Forgot to say. Being on the GBA then while custom music is a thing a lot of games will use the sappy audio format. This allows some more easy fiddling than older devices if you do want to either custom replace or maybe remove a note you don't like.
Can't find any threads about this particular issue on GBAtemp or the wider intarwebz. Saw one video on YouTube that seemed relevant, but it was some dude with the same issue, no solutions offered in the comments. :/