Conditional Button Text for Out of Stock Products and Specific Attribute Full Code https://wpsites.net/?p=115979

functions.php

add_filter('woocommerce_product_add_to_cart_text', 'custom_combined_add_to_cart_button_text', 10, 2);
add_filter('woocommerce_product_single_add_to_cart_text', 'custom_combined_add_to_cart_button_text', 10, 2);

function custom_combined_add_to_cart_button_text($text, $product) {

    if ( ! $product->is_in_stock()) {
    
        return __('Out of Stock', 'woocommerce');
        
    } else {
    
        $attributes = $product->get_attributes();
        
        if (isset($attributes['pa_custom_attribute'])) {

            $terms = wp_get_post_terms($product->get_id(), 'pa_custom_attribute');

            foreach ($terms as $term) {

                if ($term->slug == 'get_quote') {

                    return __('Get Quote', 'woocommerce');

                }
            }
        }
    }
    return $text;
}