if / elseif statements not working correctly?

so i have woocommerce based shop, and im selling for example CAKE if customer adds 4 cakes, i want 1 box to be added in the cart automatically, if customer adds more than 4 cakes i want to add another box (different product id), and so on. here is my code which im doing it:

add_action( 'woocommerce_add_to_cart', 'prefix_add_additional_product', 10, 6 );
/**
 * Adds additional product to cart based on the quantity of an added product
 */
function prefix_add_additional_product( $cart_item_key, $product_id, $quantity, $variation_id, $variation, $cart_item_data ) {
    $category = 'test';
    // Get the cart
    $cart = WC()->cart->get_cart();

    // Nothing, if the cart is empty
    if ( 0 == count( $cart ) ) {
        return;
    }

    // Enter the free product ID
    $additional_product_id = 2832;
     $additional_product_idd = 2831;
    $additional_product_iddd = 2833;


    // Don't add accessory when adding the same accessory
    $added_product_id = 0 < $variation_id ? $variation_id : $product_id;
    if ( $added_product_id == $additional_product_id ) {
        return;
    }
     if( has_term( $category, $product_id ) ){    
        $cart_id = WC()->cart->generate_cart_id( $additional_product_id );
        $prod_in_cart = WC()->cart->find_product_in_cart( $cart_id );
     }


    // You can add checks for specific product ID or some other requirements here

   if( $additional_product_quantity = (int) ( $quantity < 4 )){

    if( ! $quantity < 4) {
        WC()->cart->add_to_cart( $additional_product_id, $additional_product_quantity ); }
   }
   elseif( $additional_product_quantity = (int) ( $quantity > 4 )){
       WC()->cart->add_to_cart( $additional_product_idd, $additional_product_quantity );
     
     }
}

code is working normally, but problem is that, when i add more than 5 cakes in the cart it still adds box which should be added only if im buying less than 4 cakes, what am i doing wrong here?