The plugin is Booking Activities. Below is the Github page where the plugin provides a mechanism to move the calendar based on the settings. As I mentioned, I tested the plugin with Kadence and Themeisle.
https://github.com/bookingactivities/booking-activities/blob/741db4641404df1cc962792e2c1934ef47a94d3a/controller/controller-woocommerce-frontend.php#L1005
/**
* Move the add-to-cart form below the product summary
* @since 1.7.16
* @version 1.16.5
*/
function bookacti_move_add_to_cart_form_below_product_summary() {
global $product;
if( ! $product ) { return; }
if( has_action( 'woocommerce_after_single_product_summary', 'woocommerce_template_single_add_to_cart' ) ) { return; }
if( ! bookacti_product_is_activity( $product ) ) { return; }
if( bookacti_get_setting_value( 'bookacti_products_settings', 'wc_product_pages_booking_form_location' ) !== 'form_below' ) { return; }
$priority = has_action( 'woocommerce_single_product_summary', 'woocommerce_template_single_add_to_cart' );
if( $priority === false ) { return; }
remove_action( 'woocommerce_single_product_summary', 'woocommerce_template_single_add_to_cart', $priority );
add_action( 'woocommerce_after_single_product_summary', 'woocommerce_template_single_add_to_cart', 5 );
add_action( 'woocommerce_before_add_to_cart_form', function() { echo '<div class="bookacti-wc-fullwidth-cart-form">'; } );
add_action( 'woocommerce_after_add_to_cart_form', function() { echo '</div>'; } );
}
add_action( 'woocommerce_before_single_product_summary', 'bookacti_move_add_to_cart_form_below_product_summary', 10 );