Thank you for this. This is not ideal either, because I need to send the docx to native word users. They will be taken aback by this but have a surprisingly high tolerance for formatting issues. It's okay for the formatting to get messed up when editing, but I don't think they will accept being confined to a text box for each section.

Did you create the pdf from something? Maybe export from there would be easier...

This is a nice thought. I used asciidoctor-pdf. I know I can output to .html natively with asciidoctor.

The other tool I encounter this with is latex.

If you can export to html or have the latex source, you can use pandoc to make a much better conversion to word. A pdf file simply does not have enough information to create a useful docx.