It occurs to me that I don’t know what an “irreparably damaged” frame is. I did not annotate all of the red splotches or emulsion scratches but these are the ones that stuck out to me. I guess it really boils down to how much motion is in the frame and how much time you want to spend trying to fix it.
Those “red splotches” are the mould. By the sound of it they will either all need to be replaced with another source, or you’d need to stack the print scans and erase the damage. That may be possible, they are digitally pin-registered/aligned to the sprocket holes, but I’d be guessing they won’t align themselves perfectly without further work as they’re in two different languages, hence made from different inter-negs.
MikeV stacked his scans to erase damage without needing to resort to interpolating the damaged areas, I think poita’s got the same strategy in mind. It must take incredible computing power to do that! Then again, I guess 4K is only a rather recent thing anyway - what was the first film scanned at 4K does anyone know?