I use the gallery field for woocommerce products, because it has more possibilities.
The images are already uploaded in media.
Is it possible to make an import file to attach the images into the gallery.
Or… how to attach the images to a product with a woocommerce csv file?
I recommend the WP All Import plugin along with its ACF add-on and WooCommerce add-on. I use those plugins all the time to import data and it’s always worked out great!