Hello,
Then the problem didn't come from the temp path (needed only to generate charts and download images when importing HTML) but missing permissions to generate the DOCX output.
On https://www.phpdocx.com/documentation/practical/creating-a-new-document you can find the documentation about working with the target output. Premium licenses also include a stream option to don't generate DOCX as file but as stream.
We move your request to the web team to consider adding more text about setting the folder output and its name.
Regards.