Symfony Playgound with its Container and a custom configuration

test.php

<?php

use App\Kernel;

require __DIR__.'/vendor/autoload_runtime.php';

use Symfony\Component\Console\Output\StreamOutput;
use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
use Symfony\Component\DependencyInjection\ContainerBuilder;

return function () {
    $k = new class('dev', true) extends Kernel implements CompilerPassInterface {
        public function process(ContainerBuilder $container)
        {
            $container->getAlias('logger')->setPublic(true);
            $container->getDefinition('monolog.handler.console')->setPublic(true);
        }
    };
    $k->boot();
    $c = $k->getContainer();

    $c->get('monolog.handler.console')->setOutput(
        new StreamOutput(fopen('php://stdout', 'w'),
        StreamOutput::VERBOSITY_VERY_VERBOSE,
    ));

    $logger = $c->get('logger');
    $em = $c->get('doctrine.orm.entity_manager');

    // Start of playground
};

Very good! Thanks you.
It is worth mentioning that this command can be executed using symfony php test.php