Editing DNG RAW files on iPhone 12 Pro Max - why can't I convert to JPEG on the phone?

It seems a waste of time to edit Apple ProRAW DNG files in the Photos app on the iPhone 12 Pro Max, since when I transfer them to my desktop computer and open them in Photoshop or Lightroom my edits on the phone are not retained and I have to start over again. It would be VERY convenient to be able to save the edited photos as JPEG on the phone, as I love the way the edits look. Is there a solution?