For me, I had to connect my Iphone XR to Windows 10 either installed into my Macbook Pro or via VirtualBox.
From there, my Iphone will prompt to "Trust" my Windows 10, which I tapped on "Trust."
After that, I can access my iphone's DCIM folder to drag all of it over to my Windows 10.
I had an issue with a MOV H.265 file that was 18 minutes long in my iphone that would not transfer via Windows 10.
So in my iphone's Photos app, I selected this 18 minute clip and made it "Save To Phone." The saving process makes the app convert the clip. From there, I could transfer this 18 minute clip.
However, when I set my iphone to H.264 MOV, the codec that takes up more space, but is more compatible to most if not all devices these days, has no issue transferring over when it's a long and large file sized clip.
I guess you and I are doing QA testing for apple for free.
When my business booms one day, I'll reach out to hire you. As I don't like to freeload or freeloaders. Cheers.