The problem is that your sample is not using the correct tag. On https://www.phpdocx.com/documentation/introduction/html-extended-to-word-PHP you can read the list of supported contents and their default tags (that can be overwriten if needed).
For example, to generate a new section you need to use the following tag:
<phpdocx_section data-sectionType="nextPage" data-paperType="A3-landscape" />
This is using phpdocx_section (not phpdocx_addSection). Also please note you need to use data-paperType (not dataPaperType as your code is using).
In the samples included in the Premium package you can find a script that creates a section with HTML Extended: sample_6.php