First English comment! I own one of these - got it back in May 2020. Back in the day (from 2016 to about 2022), I was a play-yan superfan, now with small hyperfixations that come back once in a while. Mine didn't come with the MediaStage disc but someone, somewhere, needs to put it online so I can get it and mess with it myself. I wanna make play-yan formatted videos. If you could archive the MediaStage thing, let me know!
Sure, I uploaded it to Google Drive, but it probably only works on windows XP and requires Japanese support drive.google.com/file/d/1-7KhKe8Z2lumDSHrtnkPcQLziuoWlL-k/view?usp=sharing