I did a search, and found suggestions implying that an iPhone 11 would work, but that newer iPhones don’t. I found lots of people suggesting that DxO ought to add iPhones.
I found lots of posts, including this one:
Which led to:
My iPhone actually is an iPhone 11 Pro, so there is a chance that it might be appropriate, but I haven’t yet found a post suggesting which “raw file” app for my phone might work.
I don’t think there is any good answer, but I do have lots of time to start practicing on my own, and try to find something useful.
Thanks for the advice; if nobody comes up with a useful suggestion, I’ll create yet another new post. Mark is right - yes it has been raised dozens of times, but nobody has yet found a solution for newer iPhones. On the other hand, PhotoLab wasn’t supposed to work on my Leica M8.2, but with a little trickery in the EXIF data, I got it working anyway.