If you have macOS you don't need either, just plug your iPhone open up "/Applications/Image Capture.app" and it will show your photos. You can select and drag and drop to a disk and delete them all from this app.
A VM running macOS and a script. Open Photos.app and sync with ‘Download Originals’ checked. Quit Photos.app and rsync the folder ‘Originals’ out of the app bundle and onto a NAS. Once finished, reopen Photos.app.
It’s quite horrible getting the script to run as permissions get tricky with chrontab, so I used Lingon X to schedule it.