Hello, @bagshaw50,
Variable product displays Select options title by default on the shop page and home page. Buy now title displays only for the affiliate products. So, it’s impossible that you had that title for the variable products button without additional customization. show the Add to cart title for that button on the shop page you need to display product attributes on the grid as we do on the demo using the built-in variation swatches feature https://xstore.8theme.com/product-category/pullovers/. if you want just to rename that button you can try this solution in the child theme https://www.businessbloomer.com/woocommerce-rename-select-options-button-shop-page/
Regards 8Themes Team.