I've just now realized the most complete / high-fidelity way to export photos off the iPhone with osX is not to use the Photos program (import to library, export originals, export modified or as JPEG, etc.), but rather to use the Image Capture program -- it allows you to dump the native format of all camera file contents to a folder on your drive directly.
What Image Capture does is produce exactly 1-5 or 1-6 files for every photo... for example, if you have a live-photo picture that's been edited, you'll get:
1). IMG_0001.HEIC (the original photo)
2). IMG_0001.MOV (the original live-photo video)
3). IMG_E0001.HEIC (the photo as edited in iOS Photos app)
4). IMG_E0001.MOV (the live-photo vide as edited in iOS Photos app)
5). IMG_0001.AAE (the Photos metadata file that connects all the above with lossless change-history)
*6). IMG_O0001.AAE (no idea how this is different from #5 above, but yet another Photos metadata file that *sometimes* appears; sometimes you only get #5)
If you did not edit the photo at all from the original, you will only have #1 (or if it's a live-photo, #1 + #2).
I typically don't care to keep the original if I've edited it... so whenever #5 and/or #6 are present, my preference is to delete #1-2 and keep only the "E" files of the same numbered set.
I'm curious if any of you have seen third party apps that make sense of the apple photos nomenclature above and could potentially automate this process (to basically delete the originals whenever an edited version exists in the same named IMG#).