I maybe have found the answer:
woocommerce_variation_select_change seems just like a notifier whereas the desired action can be done with:
$( ".single_variation_wrap" ).on( "show_variation", function ( event, variation ) {
console.log( variation ); // fires correctly and returns a Woocommerce product object
} );
Found here:
https://sarathlal.com/get-variation-product-data-on-selecting-variation-options-woocommerce/