Add Read More tag to Category Index page

How can I add a Read More tag to the text of the description on a category index page?

I’ve tried the native tag that comes with WordPress and several plug-ins. I can get a plug-in to work on a Page, but it has no effect when used in the description of a Category. I currently use the “Read More Without Refresh” plugin on my pages and it works fine.

The page I wish to add a Read More tag to is https://www.midwaychristian.org/category/disciples-sermons/

Thank you!