The filename fallback must only contain ASCII characters.

download-file-non-ascii-chars-laravel.php

<?php 
  $file = Storage::disk('my_storage_name')->get($originalFileName);

  $response = response($file)
      ->withHeaders([
          'Content-type' => 'application/force-download',
          'Content-Transfer-Encoding' => 'Binary',
          'Content-Disposition' => 'attachment;filename='.$newFileNameWithNonAsciiChars,
      ]);
  return $response;
?>