Change Add to cart button text only on shop page - WebToffee WooCommerce Subscription

functions.php

add_filter('woocommerce_product_add_to_cart_text', 'webtoffee_archive_custom_addtocart_button_text', 10, 2);

function webtoffee_archive_custom_addtocart_button_text($var, $instance)
{
    if(is_shop()){
        
    $var =  __('Read More', 'woocommerce');
    
    }
    return $var;
}