Photo Library Size makes no sense.

I have a photo library of 45,000+ photos dating from the 1870's to today. It is 383.8 GB on a 2 TB Mac OS Extended formatted external SSD. Latest MacOS, Mac mini, latest version of Photos, etc...

Recently my secondary backup drive died. So I bought a new drive but instead of putting a single photo library on the backup I decided to make a stand alone library containing the years 1870 to March 2014 (the day my twins were born). I decided to do this first by just exporting those photos. And and then creating a new library with that export. A total of 12,331 photos, with their date and locations. The new library is 24.91 GB, about what I expected. The issue with this is all the name tags are gone.

So I decided to duplicated the original file and delete all the photos prior to January 1, 2010. This retains the name tags. Also retains the edits. But instead of 12,331 photos this library contains 5,418 photos. I deleted the recently deleted photos folder, and all existing albums, projects, etc. The only difference between these two truncated libraries are:

1. The smaller library, in number of photos, has roughly 7000 fewer or 43.9% the number of photos than the larger. In fact, the 5419 photos in the smaller library are shared by both libraries.
2. The smaller library (in number of photos) has all the name tags while the larger has none.
3. The smaller library has the original photos (note, I rarely edit my photos), the larger made from the exported photos did not have the originals exported.

So I am expected this smaller library, in number of photos, to be less than 24.91 GB but it is 118.63 GB.

From the original library of all photos from 1870 to today, I made a duplicate library and deleted, the 5419 photos from 1870 to 2010 and that file dropped the size of that file from 383.8 GB to 371.42 GB. That 12 GB difference is the roughly the size I am expecting my truncated file for those years to be, not 118.63 GB!

I've cleared everything, I deleted everything, the file is on a brand new SSD, this extra 100+ GB has be to some resource file attached to the original file. How do I get rid of it?

Outside of creating new libraries and then re-tagging all the names, which I don't want to do, I think wasting 100 GB on a SSD is crazy.

Thanks -- FYI -- Been using Apple Products since the original Apple II with 16K and a tape drive. Back when the programmers knew something about memory management. :)

Cheers