[Android] Ikemen Revolution decrypted mp3 files?

[NIS_help]

I extracted some BGM .mp3 audio files from the Ikemen Revolution game using Nox:

Some are from the apk - which play fine.
Others are from the data that has to be downloaded afterwards, and these are not playable.
There seems to be a folder it decrypts a few files at a time to in .mp3decy format. One of these songs (from the original apk) plays fine, the other is decrypted from the data I mentioned above, and it is a different file in hxd but still sadly does not play.

There is also a json file if it helps at all - is anyone familiar with this and could the music be extracted?

I have attached a Mega link of sample files- I would really appreciate the help!
https://mega.nz/file/1F80UCCa#PUOmC5xfFjoEiPicA_0LvXlaGN2C0B5fUTJZlSijPqU