Last time I tried to parse .docx it was full of opaque binary blobs, it might be a zip but parsing the data is like summoning arcane magic. It might have changed in the last decade, but considering the Microsoft has no incitement to make the situation better parsing it is always going to be a "fun" exercise.
I was writing an indexer (ca. 2018), and I don't recall encountering opaque blobs, but parsing the ZIP file and XML (with a small C XPath scanner) was straightforward.