Transfer of pictures and movie clips from iPhone to PC

I can´t find a way to transer the pictures from my iPhone 11 Pro to any PC, even though I follow the instructions listed on Apples and Microsofts web pages. If I try to import via Photos in Windows, a message "An error occured" pops up and if I try to copy the pictures from the DCIM-folder to any folder, I get "Unit can´t be reached" - I translated these messages from Swedish, so the English original message can be slightly different. I have tried to transfer the pictures to three different PCs (Windows 10), so I´m fairly confident the problem lies with the iPhone. There is no problem to sync the phone via iTunes though. How should I proceed?