I cannot comment much on Windows flash script - never used it. Even don't know whether anyone else has used Windows to flash using that script. The script is taken from SFOS repos and I can only hope it works.

You can probably run through executed commands and see where it fails specifically. In the end, it should be calling fastboot. For searching, it should try to find device using fastboot output, if I remember Linux script correctly. Probably something similar is done in Windows.

But I let users with better Windows experience to guide you through.