PDF size reduction for Magento 2

AbstractPdf.php

<?php

declare(strict_types=1);

namespace MyNamespace\Sales\Model\Order\Pdf;

use Magento\Sales\Model\Order\Pdf\AbstractPdf as MagentoAbstractPdf;

/**
 * Drastically reduce size of PDF by changing fonts
 */
abstract class AbstractPdf extends MagentoAbstractPdf
{
    protected function _setFontRegular($object, $size = 7)
    {
        $font = \Zend_Pdf_Font::fontWithName(\Zend_Pdf_Font::FONT_TIMES);
        $object->setFont($font, $size);
        return $font;
    }

    protected function _setFontBold($object, $size = 7)
    {
        $font = \Zend_Pdf_Font::fontWithName(\Zend_Pdf_Font::FONT_TIMES_BOLD);
        $object->setFont($font, $size);
        return $font;
    }

    protected function _setFontItalic($object, $size = 7)
    {
        $font = \Zend_Pdf_Font::fontWithName(\Zend_Pdf_Font::FONT_TIMES_ITALIC);
        $object->setFont($font, $size);
        return $font;
    }
}

di.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">    
    <preference for="Magento\Sales\Model\Order\Pdf\AbstractPdf" type="MyNamespace\Sales\Model\Order\Pdf\AbstractPdf" />
</config>