Hi.
I remember the exclamation Mark.
I had to find a fast method to search through the 82.000 Photos.
My solution was:
In the Photos app, corner left up, click on the ''Photos'' category.
Middle up, click on the ''All Photos''.
You will see some of your photos in a Thumbnail view.
Scroll up to your FIRST photo in the library.
Double click on the first photo in the library so that it opens wide.
Under this photo, you will see a row of thumbnails of the next photos.
Here you can scroll to the right with the keyboard arrow.
In this row is where you will see the corrupted photos differently than the normal ones, because they will always be the colour GREY (at least for me they were).
If you have good eyes, you can keep the right arrow pressed, and just follow the flow of thumbnails in the bottom row.
This is how i have found all my corrupted photos. They were easy to recognise..., they were all grey.
After I have passed the years 2014-2015 I have checked the ''Curation'' status, and it was complete.
Best of luck !!