Moving forward. It doesn't reformat the previously taken images. A stupid workaround would be screenshotting the photo, as screenshots are saved as jpgs always.
Discussion
Cool, tried that and it works. Janky but it works! Thanks. Sweet shortcut gonna be a life saver ⚡️
Updated the shortcut so that it throws an error if you’re trying to upload an HEIC type file: https://www.icloud.com/shortcuts/bde8c50b19084bbc8d0f6f7e5868530c