it is possible to create products via
wp_insert_post() (https://lukasznowicki.info/insert-new-woocommerce-product-programmatically/). Regarding variable products I found this answer: https://stackoverflow.com/questions/47518280/create-programmatically-a-woocommerce-product-variation-with-new-attribute-value
In the end of the answer there is a link to another answer that seems to be the first step in this solution.
Did not try anything of that, but maybe it helps?