Problem downloading large video file from iPhone using ImageCapture

I have two videos, taken with my iPhone - one 9+GB and the other 11+GB.

I have been trying all day to download them from my iPhone, using ImageCapture. The application sends up a dialogue that says that it’s converting the files, but then I get an error message. It’s only for the two large files. Other videos, taken today, downloaded from the iPhone to the iMac, without any problem.

I was able to get copies of the two. large videos using AirDrop (took a very long time) and the Photos app, but the files are smaller - the AirDrop files are each about 2GB smaller than the file size of those, on the iPhone, as displayed on the ImageCapture app. The video downloaded with Photos is about half the size of the original file. The other, smaller videos that I downloaded, today, using ImageCapture, are exactly the same size, on the computer, as those listed on the ImageCapture application (displaying the photos and videos on my iPhone).

Is there a 3rd party app that I can use to download the photos and videos, on the iPhone?