Duplicate video files for all my projects: eliminate duplicates?

I have been using Elements for maybe 10 years, several versions, but I am "weak" on the relationship of projects to the organizer.  Now, with 2021, I find I have duplicates of all my video files, which "eats" a lot of disk space.

I would like to eliminate the duplicate files.

Here is how I got to this point:

• 10 years ago, I started creating projects in Premiere Elements.  In general, I created a project folder (external to Premiere), copied my video files to the folder (external to Premiere), then created a project and added the video files using Premiere.
• Somehow, the video files SEEM to have been added to the Organizer, but I never noticed that.
• Now, I just upgraded again (2021 now), and I am trying to manage my files the "Adobe Way", so I:
• A) Backed-up my catalog from v2018 to an external drive.
• B) Backed-up my project folders to an external drive.
• C) Removed v2018, installed v2021
• D) Restored my catalog.
• E) Copied my project folders back to my laptop.

Now, all the video files exist in 2 locations:

• The folder where my catalog exists.
• The folders where my Premiere projects exist.

Question: Is there a way I can eliminate the duplication, AND have things structured so when I upgrade next time, repeating A-E above, I do not have duplicates?

Ideally, the projects would be part of the Organizer backup/restore, but it seems like projects have to be managed separately.

Appologies for the long post, but I would really like to clean-up how I manage my catalog and projects.