Persona5 quick bms script didn't work at all, but the engine and file format is almost the same. The folder where the audio files are stored is named root. I will give a sample of the files, including .rdb and .rdx files that I found.
https://www.mediafire.com/file/dtjcdy8igjtkm8n/b6e28c40.rar/file
https://www.mediafire.com/file/dtjcdy8igjtkm8n/b6e28c40.rar/file