<?php

ini_set('display_errors', 1);

use Magento\Framework\App\Bootstrap;

require __DIR__ . '/app/bootstrap.php';

$bootstrap = Bootstrap::create(BP, $_SERVER);

$obj = $bootstrap->getObjectManager();

$state = $obj->get('Magento\Framework\App\State');
$state->setAreaCode('frontend');

$config = $obj->create('Magento\Framework\App\Config\ScopeConfigInterface');
echo $review->getValue('path/to/config', \Magento\Store\Model\ScopeInterface::SCOPE_STORE);
exit;

You just need to replace path/to/config with your config path

<?php

ini_set('display_errors', 1);

use Magento\Framework\App\Bootstrap;

require __DIR__ . '/app/bootstrap.php';

$bootstrap = Bootstrap::create(BP, $_SERVER);

$obj = $bootstrap->getObjectManager();

$state = $obj->get('Magento\Framework\App\State');
$state->setAreaCode('frontend');

$config = $obj->create('Magento\Framework\App\Config\ScopeConfigInterface');
echo $config->getValue('path/to/config', \Magento\Store\Model\ScopeInterface::SCOPE_STORE);
exit;

You just need to replace path/to/config with your config path