phpwkhtmltopdf engine pdf printing configuration issues
/opt/drupal/vendor/mikehaertl/phpwkhtmltopdf/src/Pdf.php: cannot open
?php: No such file

You need to install the missing library using composer
composer require mikehaertl/phpwkhtmltopdf

In addition, you might also need h4cc/wkhtmltopdf, see Entity Print documentation