PHPSpreadsheet: styling completely ignored

Trying to add styling to PHPSpreadsheet’ cells:

$spreadsheet = new Spreadsheet();
        $sheet = $spreadsheet->getActiveSheet();

        $irow = $icol = 1;
        foreach ([
                     'Operation type',
                     'Name',
                     'Status',
                     'Start',
                     'End',
                     'Duration'
                 ] as $title) {
            $sheet->setCellValue([$icol, $irow], $title);
            $sheet->getStyle([$icol, $irow])->getFont()->setBold(true);
            $sheet->getStyle([$icol, $irow])->getAlignment()->setVertical(Alignment::VERTICAL_TOP);
            $icol++;
        }
        //
        $writer = new Xlsx($spreadsheet);
        $writer->save('hello world.xlsx');

Finally, I see properly filled Excel sheet without any styling – no bold font, no vertical alignment.

What’s wrong?

UPDATE:

1. getStyle accepts array of 4 ints instead of array of 2 ints in setCellValue:

    /**
     * Get style for cell.
     *
     * @param AddressRange|array<int>|CellAddress|int|string $cellCoordinate
     *              A simple string containing a cell address like 'A1' or a cell range like 'A1:E10'
     *              or passing in an array of [$fromColumnIndex, $fromRow, $toColumnIndex, $toRow] (e.g. [3, 5, 6, 8]),
     *              or a CellAddress or AddressRange object.
     */
    public function getStyle($cellCoordinate): Style

2. getStyleByColumnAndRow marked as deprecated. Recommends to use getStyle instead