1/ You may simply select “Any size” for your variations -> https://prnt.sc/QL7DVNBcnDB4
2/ You may read next topic -> https://www.8theme.com/topic/product-variation-images-generating-in-xml-file/ – The user uses WooCommerce XML feed for Skroutz & Bestprice Pro version and we are already compatible with that plugin but you may try to search any free plugin that allows import/export custom fields, for example, -> Advanced Order Export For WooCommerce.
Our variation gallery field id -> et_variation_gallery_images ( it is an array of images ids for each variation )
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