i cant get PHPSpreadSheet working. It works locally. Server PHP is 7-73. All extensions are active.
I know that PHPSpreadSheet is already implemented in Gibbon.

In which folder/file can i find your usage for PHPSpreadSheet? Maybe i can use that knowledge to solve this problem.

Simple Code with template in same folder:
require ‘vendor/autoload.php’;
use PhpOffice\PhpSpreadsheet\Writer\Xlsx;
use PhpOffice\PhpSpreadsheet\Spreadsheet;
use PhpOffice\PhpSpreadsheet\IOFactory;

Good. Found the solution.
Had to change the path.