I’m experiencing the same problem (with CV-Toolbox_20191023b on my - Catalina OS - iMac) that others have reported here.
To be clear, I did install CV Toolbox as instructed on your Cineversity website.
The installation was within the most recent Mac OS version of C4D S22.
After closer examination, I discovered that there is another plug-in folder within the last folder you’re directed to. See the related image file below. Drop the CV Toolbox folder in that plug-in folder and CV Toolbox will appear in your drop-down Extensions menu.
I discovered that two of the CV Toolbox menus exhibit grayed-out entries. See attached image files below. If you found the same to be true, please make note of it here to aid in resolving or perhaps explaining those questionable menu entry appearances or states. It might be that another action or process might have to be activated in order for those menu entries to be accessible.