Well, it turns out, based on feeedback from a django-cms Fellow on Discord, when one installs django-cms manually it does not have all the bits one gets when it is installed using Docker. There is nothing in the official online documentation for django-cms to let you know that a manual installation is not really usable, nor does the documentation say what parts are missing and how to install them to get a fully functional installation. In fact, the documentation says there are three ways to install django-cms - on Divio where you pay for hosting, using Docker, and manually. The reader is lead to believe the manual installation is no different than the Docker installation.

The manual installation is no different than a normal django installation. Create a virtual environment and then run various django-cms commands inside that virtual environment to install and setup django-cms.

After spending over a week chasing my tail as to why I can't get a manual installation working with my own template, I am moving on to a better solution for my clients since I still do not know what bits are missing nor how to install them. However, the django-cms Fellow did offer me the opportunity to edit the django-cms documentation.