Hello,
You can create and use a custom list style (https://www.phpdocx.com/api-documentation/layout-and-general/create-Word-custom-list-style-with-PHP) with the options that suit your needs and apply it to a paragraph or a custom paragraph from HTML or using addText.
Instead of applying the third level of a custom level list, that phpdocx doesn't allow to apply as first element of the content based on the depth, you could generate a custom list style that the first level has the required properties and then apply it to the paragraph or HTML or custom paragraph style.
Regards.