I seem to have come into this problem somewhere in the middle of what some here are addressing. I am using ARCGIS Pro 2.8. I cannot believe this is that hard. Therefore there has to be something I am missing.
I have been creating an involved project on a common drive. This avoids the C:\ issue. Within the home folder for this project I have saved different versions of the project (save as, a new .aprx). This was done to minimize the damage if something got corrupted. This approach is of limited value because the copy is still tied to the original project geodatabase.
One goal is to create a clean copy of the project, minus the various intermediate, test and otherwise no longer needed model, layer files and etc. To be clear, I want my original project map geodatabase intact, and the new copy to have only the minimum of features and associated materials. There are a few more things to be done, like designing my layer files for symbolizing. At that point I will want to create a final template. It must allow a future user to begin with all the base files, models and symbology .lyr files associated with this assignment. These copies, hypothetically can be anywhere, but are intended to be stored on the common drive, in a project folder.
All without damaging the latest, working map project:
Goal 1 Clean up and finish a project map
Goal 2 create a Project Template for sharing.
At some point I want to delete older copies and perhaps the working map project, but that should be a matter of deleing copies, at no risk to later versions.
First I created another copy of the project map. To it I added a 2nd copy of the original project geodatabase and renamed it. Then changed the source property for each layer to be the new geodatabase.
The project toolbox was still the original project toolbox. Also, every step in a project model/tool pointed to the original project map. The output appears in the new map project. It seems a toolbox either cannot be renamed or copied or doing so requires some not obvious steps.
Finding this unwieldy-
I reopened the last working copy of the map project and shared it as a project template.
Upon opening the template and saving a new project; it has two geodatabases, one empty and one with the original layers. Both appear to be tied exclusively to the new map project. It also has two tool boxes, both with the original project models/tools.
The good news is that the project models/tools look to be tied to the new map project.
This is a lot of steps. This cannot be the intended process.