You will need to install a user script manager extension to install this script.
When a DOCX link is clicked using the mouse shortcut, a popup dialog will be shown to indicate the file loading progress. If the file size is known, a percentage number will be shown. Otherwise, the number of data bytes will be shown.
This script uses the mammoth.js library for handling the DOCX to HTML conversion. https://github.com/mwilliamson/mammoth.js
This script is compatible with Tampermonkey and Violentmonkey addons. For Greasemonkey addon, it may be compatible with v3.x (untested), but it's not compatible with v4.x due to its incomplete implementation.
When used with Tampermonkey addon, Tampermonkey will ask whether to allow or reject the network request made by the script for loading the DOCX document. This is a security mechanism by Tampermonkey, because background network request to other domain is considered as a risk. However, this network request is required, so please allow it either temporarily or permanently. But do so after checking whether the shown Destination URL matched the link which was clicked. i.e. the Destination URL should point to a DOCX file also.