I solved this after making some researching
Through Overriding New Shipment Save Controller using a Plugin
app/code/Vendor/CustomModule/etc/adminhtml/di.xml
<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
<preference for="Magento\Shipping\Controller\Adminhtml\Order\Shipment\Save"
type="Vendor\CustomModule\Controller\Adminhtml\Order\Shipment\Save" />
</config>
app/code/Company/Module/Controller/Adminhtml/Order/Shipment/Save.php
<?php
namespace Company\Module\Controller\Adminhtml\Order\Shipment;
class Save extends \Magento\Shipping\Controller\Adminhtml\Order\Shipment\Save
{
//did my custom logic here
}
reference: Magento 2 - sales_order_shipment_save_after