Magento 2 override the cutomer account loginpost controller

You need to rewrite the customer loginPost plugin file as per the below

<?php

namespace VENDOR\MYMODULENAME\Plugin\Customer;

class LoginPost
{
    public function __construct(
        \Magento\Framework\App\Action\Context $context
    ) {
        $this->_request = $context->getRequest();
        $this->_response = $context->getResponse();
        $this->resultRedirectFactory = $context->getResultRedirectFactory();
        $this->resultFactory = $context->getResultFactory();
    }

    public function aroundExecute(\Magento\Customer\Controller\Account\LoginPost $subject, $proceed)
    {           
        $login =  $this->_request->getPost('login');     
        $custom_redirect= false;

        $returnValue = $proceed();            

        if (isset($login['press_room_page'])) {
            $custom_redirect=true;
        }
        if (isset($login['press_room_page']) && $custom_redirect) {
            $resultRedirect = $this->resultRedirectFactory->create();
            $resultRedirect->setPath('mycustomlogin/index');
            return $resultRedirect; 
        }
        return $returnValue;
    }
}