php - Laravel: how to change startcell when exporting using a template file

one text

Laravel Framework 5.8.38
maatwebsite/excel 3.1.19

I'm trying to export using a template file.
the following code is working but "startCell()" doesn't seem to work.
it's always start from "A6" in export file.

how should i do in this case.

class TestExport implements FromQuery, WithEvents, WithCustomStartCell, WithStrictNullComparison
{
    public function setTemplate(string $template_file)
    {
        if (file_exists($template_file)) {
            $this->template_file = $template_file;
        }
        return $this;
    }

    public function startCell(): string
    {
        return 'A3';
    }

    public function registerEvents(): array
    {
        return [
            BeforeExport::class => function (BeforeExport $event) {
                if (is_null($this->template_file)) {
                    return;
                }
                $event->writer->reopen(new LocalTemporaryFile($this->template_file), Excel::XLSX);
                $event->writer->getSheetByIndex(0);

                $this->calledByEvent = true;
                $event->writer->getSheetByIndex(0)->export($event->getConcernable());
                return $event->getWriter()->getSheetByIndex(0);
            },
            BeforeWriting::class => function (BeforeWriting $event) {
                $event->writer->removeSheetByIndex(1);
                return;
            },
        ];
    }
}