Woocommerce: Temporarily Disable Shop Page - While on Vacation

 https://passwordprotectwp.com/disable-woocommerce-shop-page/

/**
 * @snippet       WooCommerce Holiday/Pause Mode
 * @how-to        Get CustomizeWoo.com FREE
 * @sourcecode    https://businessbloomer.com/?p=20862
 * @author        Rodolfo Melogli
 * @testedwith    WooCommerce 3.5.1
 * @donate $9     https://businessbloomer.com/bloomer-armada/
 */
// Trigger Holiday Mode
add_action ('init', 'bbloomer_woocommerce_holiday_mode');


// Disable Cart, Checkout, Add Cart
function bbloomer_woocommerce_holiday_mode() {
   remove_action( 'woocommerce_after_shop_loop_item', 'woocommerce_template_loop_add_to_cart', 10 );
   remove_action( 'woocommerce_single_product_summary', 'woocommerce_template_single_add_to_cart', 30 );
   remove_action( 'woocommerce_proceed_to_checkout', 'woocommerce_button_proceed_to_checkout', 20 );
   remove_action( 'woocommerce_checkout_order_review', 'woocommerce_checkout_payment', 20 );
   add_action( 'woocommerce_before_main_content', 'bbloomer_wc_shop_disabled', 5 );
   add_action( 'woocommerce_before_cart', 'bbloomer_wc_shop_disabled', 5 );
   add_action( 'woocommerce_before_checkout_form', 'bbloomer_wc_shop_disabled', 5 );
}
// Show Holiday Notice
function bbloomer_wc_shop_disabled() {
        wc_print_notice( 'Our Online Shop is Closed Today :)', 'error');

}