Simply add following line into your overwrite class.
$resultRedirect->setUrl($this->url->getUrl('customer/account/login'));
OR
You can do it using plugin as follows
Vendor/Module/etc/frontend/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">
<type name="Magento\Customer\Controller\Account\CreatePost">
<plugin name="sr_Customer_Account_CreatePost" type="Vendor\Module\Plugin\Customer\Account\CreatePost" sortOrder="1"/>
</type>
</config>
Vendor/Module/Plugin/Customer/Account/CreatePost.php
namespace Vendor\Module\Plugin\Customer\Account;
class CreatePost
{
/**
* @var \Magento\Framework\UrlInterface
*/
protected $url;
/**
* @param \Magento\Framework\UrlInterface $url
*/
public function __construct(
\Magento\Framework\UrlInterface $url
)
{
$this->url = $url;
}
public function afterExecute(
\Magento\Customer\Controller\Account\CreatePost $subject,
$resultRedirect
) {
$resultRedirect->setUrl($this->url->getUrl('customer/account/login'));
return $resultRedirect;
}
}