Have a plugin (interceptor) run once per session

So, I have this plugin for our project (drop-shipping marketplace), which redirects vendors without signed contracts to the contract signing page. The thing is, as it is, it infinitely redirects whenever the vendor tries to go to his order page for instance, which is severely limiting his experience with the website. I was wondering if there’s a way to make it only work once per session, redirecting the user once and not again if he chooses not to sign the contract now. I tried using SessionManagerInterface to store variables in the session and check for it on the plugin, but didn’t get very far. Here is the plugin as of now (working but redirecting infinite times). Sorry if this is a simple question, I’m very new to Magento and PHP. Thanks for your time! 🙂

<?php
declare(strict_types=1);

namespace SlowcosUnirgyDropshipPlugin;

use UnirgyDropshipControllerVendorIndex;

/**
 * Class LandingPageRedirect
 *
 * @package SlowcosUnirgyDropshipPlugin
 */
class LandingPageRedirect extends Index
{
    /**
     * @var string
     */
    const CONTRACT_PAGE_ROUTE_PATH = 'udcontract/vendor/contract';

    /**
     * @var string
     */
    const FALSE_SUBCLASS_CONDITION = 'UnirgyDropshipPoControllerVendorAbstractVendor';

    /**
     * @var string
     */
    const SIGNED_AGREEMENT_VENDOR_ATTRIBUTE_CODE = 'contrat2016_accepted';
    
    /**
     * After Execute Method for Changing the Redirect
     * If Needed
     *
     * @param Index $subject
     * @param $result
     *
     * @return mixed
     */
    public function afterExecute(Index $subject, $result)
    {
        $helper = $this->_hlp;

        if ($helper->isUdpoActive() &&
            !is_subclass_of($subject, self::FALSE_SUBCLASS_CONDITION) &&
            !$helper->session()->getVendor()->getData(self::SIGNED_AGREEMENT_VENDOR_ATTRIBUTE_CODE)
        ) {
            return $this->resultRedirectFactory->create()->setPath(self::CONTRACT_PAGE_ROUTE_PATH);
        }

        return $result;
    }
}