Hello,
That styles, minimal of they available within the default template, are always included because they are needed to the correct running of the library. There's no option to prevent them from being included.
These styles doesn't conflict with the correct work of Word, so if you need to remove them you need to change the library or change the base template, not the docx template. To change it by your self we recommend you to search for the importStyles call of the constructor in the main CreateDocx class (around line 780).
Regards.