[jiggawatts]

To be fair, the second you export a picture from an iDevice, it auto-converts it back to JPG with SDR sRGB, to make it compatible with the terrible hardware and software in the rest of the world.

You can upload HDR videos[1] however. I put mine up on YouTube and send Android users the link. This doesn't preserve 100% of the quality, because YouTube doesn't support Dolby Vision and hence is forced to recompress the content into a HDR10 stream. Nonetheless, you get 4K 60fps HDR video that "just works" and generally looks good on any high-end device such as flagship Samsung phone.

[1] Video formats in general have left still imaging in the dust. It's absurd, but the best approach for sharing high quality photography is to encode the still images into a video, like a slide show, and then share that. How nuts is that!?

[zimpenfish]

> it auto-converts it back to JPG with SDR sRGB,

That depends on your settings - Settings → Photos → Transfer to Mac or PC allows "Automatic" (guess whether HEIC or JPG is best) and "Keep Originals" (whatever the photo was shot as). I keep mine on "Automatic" because it sends HEIC to my Mac but JPG to family members who aren't up-to-date with phones etc.