I literally did all thise steps, some of them more than once. I then succeeded in backing up the iphone to an old computer which also had the latest version of itunes. Following that I tried again on my new computer and this time it recognized the device in This PC, so at least I had access to photos and videos as a hard drive
However it will not complete a backup in itunes. It creates a file in the MobileSync backup folder, but after hours that folder is empty.
Why does my ipad and my old phone backup in itunes just fine but my brand new iphone 12 either cant stay connected to itunes or fails to backup. Why does this new iphone backup to an old computer using the same software and same updated win 10? I am out of ideas