How to: export full quality JPGs from Apple iPhone ProRAW using just Photos on the phone

Apple's ProRAW system on the iPhone 12 Pro series (onwards) is rather interesting, in that you get all the Apple 'smarts' but without the populist edge enhancement and sharpening that goes into Camera's default JPG output. But, a lot of the time, you may not see the full benefit. Yes, you can fiddle around with the ProRAW DNG files in Photos or indeed any other compatible photo editor and have a lot of fun, but what happens when you want to share around a full quality JPG with the world? For example, on the phone itself, emailing an image to someone or sharing it via iMessage or via a social media app? Happily, iOS is clever enough to convert the ProRAW DNG file 'on the fly', so you never need to worry about this. But, and here's the (really interesting) rub: what if you want a standard JPG on your MAC? Either for space reasons or because you want the desktop file to be as compatible with other apps as possible. In my case it has been to directly compare JP...