Hey, HathorM,
Thanks for responding back.
Creating a new user account is a step toward isolating the issue further. If the sync completes in a new user, it means something is going on specifically with your user account, and we can move forward with troubleshooting steps customized to that. Nothing changes with the process of syncing in a new user account.
Alternatively, if the issue persists in a new user account, it means an overall problem with the iTunes and/or Windows somewhere, and we would customize our troubleshooting based on that.
You can also try out iCloud Photos, which makes your pictures available via iCloud so all your devices can access all of your photos: Set up and use iCloud Photos - Apple Support. This will give us another option to isolate the issue to the specific photos or folders in question, or a problem with iTunes/Windows. It will also give you a different option to manage your photos.
If you need more help after that, or have additional questions or concerns, please get in touch with Apple Support directly: Contact Apple Support.
Have a good day!