MS4 - Batch Processing - MusicXML parts

I successfully made a script with the help of ChatGPT that exports the MIDI file and MusicXML file for all files in a folder. I will attach it to this thread as a txt file instead of ".sh". For the life of me, ChatGPT, and Gemini, "we" cannot figure out how to export the Piano part for the MusicXML. Fairly certain I am not messing up on this. Is this not possible with the command line?