How to export RAW original from Photos on iPad?

I’m traveling and have been importing the RAW+JPEG photos from my Canon camera directly into Photos on my iPad, so that I can distribute them, or import them into Adobe Lightroom for editing. Unfortunately, importing into Lightroom from Photos only provides the JPEG version. So … per the recommendation of several people here in discussions, I selected ‘Export unmodified original’ from Photos, but that still only exports the JPEG.

How can I get the RAW original from Photos into Lightroom … or even just download it into Files? Very frustrating.