BeforeFileAddedEvent 

<?php

declare(strict_types=1);

namespace MyVendor\MyExtension\Resource\EventListener;

use TYPO3\CMS\Core\Attribute\AsEventListener;
use TYPO3\CMS\Core\Resource\Event\BeforeFileAddedEvent;
use TYPO3\CMS\Core\Resource\Exception\UploadSizeException;
use TYPO3\CMS\Core\Utility\GeneralUtility;

#[AsEventListener(
    identifier: 'my-extension/before-file-added',
)]
class BeforeFileAddedEventListener
{
    private const MAX_UPLOAD_SIZE_FOR_PDF = 10 * 1024 * 1024;

    private const MAX_UPLOAD_SIZE_FOR_ZIP = 20 * 1024 * 1024;

    /**
     * @throws UploadSizeException
     */
    public function __invoke(BeforeFileAddedEvent $event): void
    {
        $uploadedFileData = $this->getUploadedFileDataFromGlobalFiles(
            $event->getSourceFilePath(),
        );

        if ($uploadedFileData === null) {
            return;
        }

        $uploadedFileSize = $uploadedFileData['size'] ?? 0;

        $fileRefs = GeneralUtility::split_fileref(
            $uploadedFileData['name'],
        );
        $uploadedFileExtension = $fileRefs['fileext'] ?? '';

        if (
            $uploadedFileExtension === 'pdf'
            && $uploadedFileSize > self::MAX_UPLOAD_SIZE_FOR_PDF
        ) {
            throw new UploadSizeException(
                'PDF files must not be larger than 10MB.',
            );
        }

        if (
            $uploadedFileExtension === 'zip'
            && $uploadedFileSize > self::MAX_UPLOAD_SIZE_FOR_ZIP
        ) {
            throw new UploadSizeException(
                'ZIP files must not be larger than 20MB.',
            );
        }
    }

    private function getUploadedFileDataFromGlobalFiles(
        string $tmpName,
    ): ?array {
        foreach ($_FILES as $uploadedFileData) {
            if ($uploadedFileData['tmp_name'] === $tmpName) {
                return $uploadedFileData;
            }
        }

        return null;
    }
}