events/Classes/Command/RemoveAllCommand.php

<?php
namespace Wrm\Events\Command;

use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;
use TYPO3\CMS\Core\Core\Bootstrap;
use TYPO3\CMS\Core\Utility\GeneralUtility;
use TYPO3\CMS\Extbase\Object\ObjectManager;
use Wrm\Events\Service\CleanupService;

class RemoveAllCommand extends Command
{
    public function configure()
    {
        $this->setDescription('Remove all event data');
        $this->setHelp('All events and associated data will be removed.');
    }

    protected function execute(InputInterface $input, OutputInterface $output)
    {
        Bootstrap::initializeBackendAuthentication();

        return GeneralUtility::makeInstance(ObjectManager::class)
            ->get(CleanupService::class)
            ->deleteAllData();
    }
}