surely the corrections that are applied are just plain wrong?
No, if you find a good match among the existing devices, the results will be very good. Here’s how I did with iPhone 11 images when I force compatibility. I compare with Iridient Developer and Affinity Photo RAW processing.
the quality of the output files are less than ideal, meaning you might do just as well to process the files in another application
Excellent results are already wonderful. Ideal is an impossible benchmark: my husband falls short of historical heroic ideals so I will abandon him.
Which brings up the other point. Many of us are very good at correcting our photos in PhotoLab. So to be able to use most of the tools within PhotoLab means image processing will be better and even more important, faster, than in any other RAW developer.
DxO’s lock-us-out-of-our-own-software shenanigans is one of my least favourite part’s of the DxO way. It’s a major reason I would hesitate to recommend PhotoLab to other photographers, particularly casual ones.