[Adoby]

You write a script with a loop. For instance to convert all files in a folder. Or all files with docx type.

I don't use windows, so I cant give details. But try to search for "powershell loop".

Also please note that if you do the conversion in the calibre GUI and embed metadata in the epubs with unhelpful filenames, you can use most e-reader software to search/browse the books on your phone based on the metadata. I believe it is possible, using a plugin, to even add the original filename to the metadata.