Ublaboo datagrid – export to XLS/XLSX

Dear Community members,

I would like to finish part of my code, which is responsible for exporting datagrid content to XLS/XLSX (via PhpSpreadsheet library).
I was able to successfully setup CSV export (integrated in Ublaboo), but I am still struggling how to finish my code to be able to offer XLS for direct download when clicking an Export button. Please see a snippet of my code.

use App\Model\Database\Entity\Project;
use Doctrine\ORM\EntityManager;
use Doctrine\ORM\EntityManagerInterface;
use App\UI\Control\DataGridFactory;
use App\UI\Control\BaseDataGrid;
use App\UI\Control\BaseControl;
use PhpOffice\PhpSpreadsheet\Spreadsheet;
use Nette\Localization\ITranslator;

class ProjectDataGrid extends BaseControl
{

    /** @var EntityManager */
    private $entityManager;

    /** @var DataGridFactory */
    private $datagridFactory;

    /** @var Spreadsheet */
    private $spreadsheet;

    /** @var ITranslator */
    private $translator;

    /**
     * @param DataGridFactory $dataGridFactory
     * @param EntityManagerInterface $entityManager
     * @param Spreadsheet $spreadsheet
     */
    public function __construct(
        DataGridFactory $dataGridFactory,
        EntityManagerInterface $entityManager,
        Spreadsheet $spreadsheet,
        ITranslator $translator
    )
    {
        $this->datagridFactory = $dataGridFactory;
        $this->entityManager = $entityManager;
        $this->spreadsheet = $spreadsheet;
        $this->translator = $translator;
    }

    /**
     * @throws \ReflectionException
     */
    public function render(): void
    {
        $this->getTemplate()
            ->setFile(__DIR__ . DIRECTORY_SEPARATOR . 'templates' . DIRECTORY_SEPARATOR . 'projectGrid.latte')
            ->render();
    }

    /**
     * @return BaseDataGrid
     */
    public function createComponentProjectGrid(): BaseDataGrid
    {
        $datagrid = $this->datagridFactory->forBackend();
        $datagrid->setDefaultSort(['number' => 'ASC']);

        $datagrid->setDataSource($this->entityManager->getProjectRepository()->getGridDataSource());

		// ...
        // === Coluns setup here ===
		// ...

        // Export
        $datagrid->addExportCallback('export', [$this, 'generateXls'], true);

        return $datagrid;
    }


    public function generateXls($data){
        // Iterate over filtrated projects
        $sheetData = array();

        $worksheet = $this->spreadsheet->getActiveSheet();

		// ...
        // === $sheetData array contains two dimensional data for XLS ===
		// ...

        $worksheet->fromArray($sheetData);

		// ====================================
		// >>> What I should do here <<<
		// ????????????????????????????????????
		//=====================================

    }
}