I still don’t understand.
From what I understand, the Project is used as if it were a tab.
I have a “Customers” project, a “Training” project, an “Infrastructure” project, etc.
Within the project named “Customers” I have more tasks with category “customer1”, other tasks with category “customer2”, and others again with category “customer3”.
If so, in fact it is a clever way to group the actual projects that “slide” to the Task level.
However, a level is lost, because the Tasks slide to the Sub-Task level where there is nothing to better describe them.
It is a good solution in the absence of anything; this is the “Tips and Tricks” that I initially asked for.
But the smartest thing of all would be to have a higher level “Master Category”, such as a base code or plugin.
In any case, I didn’t understand the external link to what is addressed.