The issue with HEIC is that no browsers support it. None of them. Not even Safari (seriously).
It works as a format for viewing on iOS and macOS and sharing with other devices that may support it but there are currently no web browsers in use today that natively support displaying that format on the web.
That all being said, my experience is not the same as yours.
Whether I upload pictures from my Photos library to Safari on iOS or macOS the pictures already upload as a jpeg file, and providing the server has EXIF extensions enabled in PHP, it should automatically orient them correctly.
If your experience is different, what exactly are the steps you are taking to reproduce the issue? And do you experience the same issue trying to upload photos to this forum?