How to change the PDF invoice list format, in Magento2?

Question

I have managed to create a module, and overwrite the \Magento\Sales\Model\Order\Pdf\Invoice class, using the steps proposed by this answer: https://magento.stackexchange.com/a/241932/80959

My question is how do I edit the _drawItem() method?

In the original implementation all the data is sent to some product renderer object:

/**
 * Draw Item process
 *
 * @param  \Magento\Framework\DataObject $item
 * @param  \Zend_Pdf_Page $page
 * @param  \Magento\Sales\Model\Order $order
 * @return \Zend_Pdf_Page
 */
protected function _drawItem(\Magento\Framework\DataObject $item, \Zend_Pdf_Page $page, \Magento\Sales\Model\Order $order)
{
    $type = $item->getOrderItem()->getProductType();
    $renderer = $this->_getRenderer($type);
    $renderer->setOrder($order);
    $renderer->setItem($item);
    $renderer->setPdf($this);
    $renderer->setPage($page);
    $renderer->setRenderedModel($this);

    $renderer->draw();

    return $renderer->getPage();
}

I don't understand it's purpose, nor I am able to find it's source code.

Should I discard that code altogether and start drawing each value? Or is there a purpose for that renderer, case in which I might lose some functionality?