Aus einem alten Shopware 4 Projekt, vielleicht hilft’s:
$config = new \Doctrine\DBAL\Configuration();
$connectionParams = array(
'dbname' => 'xx',
'user' => 'xx',
'password' => 'xx',
'host' => 'xx.xx.xx.xx',
'port' => '3306',
'driver' => 'pdo_mysql'
);
$conn = \Doctrine\DBAL\DriverManager::getConnection($connectionParams, $config);