Currently Samsung Gallery has this feature 'Convert HEIF images when sharing' and 'Convert HDR10+ videos when sharing'.
These are handy features for when sharing images/videos to an app that doesn't support HEIF & HDR10+ format so it'll convert to JPG or respective format. The issue is that it'll only convert for 1 single image, if you decide to select multiple images it won't convert it.
If you wanted to share eg 5 photos, it won't convert since I've selected multiple images at the same time, instead I would have to share images one by one separately which seems like an inconvenience.
Imagine you had 20 HEIF format photos or 20 HDR10+ videos you wanted to share them all at the same time but couldn't because an app doesn't support it, you'll have to share those 20 photos/videos separately each time which is frustrating.
Inconviences like this will probably discourage people from using HEIF and HDR10+ file format so I'm hoping Samsung Gallery will support multiple HEIF images & multiple HDR10+ videos conversion in an update.