I have created a theme override called "retroreport" and assigned it for a specific category. It is loading the PHP files for this override just fine.

I do, however, see an error attempting to load a CSS file:

retrograde-report-2020-10-20:40 GET https://www.thechipwitch.com/components/com_easyblog/themes/retroreport/styles/style-5.4.7.min.css net::ERR_ABORTED 404 (Not Found)

It looks like you're looking for my theme override in the main code, and not in /templates/... where the override should be living.