Ginormous PSD files when working on photos

I'm editing 25mb NEF files shot on my Nikon D750. First from Bridge to Camera Raw, then in photoshop. I use the Nik software plugin in Photoshop.

When I save my work to a PSD, the files are huge. Like 300mb for a single photo.

I've been looking around and people are or were talking about the "DocumentAncestors" in the metadata. I can see the data in there.

I've tried one of the scripts I found to remove the DocumentAncestors, but to no avail.

1. Is the DA really the problem?

2. If so, how do I get that bloating crap out of my files?

3. If not, WTF?

I uninstalled Bridge and PS CC. Rebooted my Mac, then reinstalled Bridge and PS CC before Doing the experiment below.

I just now found a file I edited in Mar of 2019. The edited but uncropped PSD was 217.9mb. I had saved a 5x7 cropped version back then, and it was only 38mb, still big, but manageable. I just re-cropped the "original size" PSD to the "front Image" ratio and put 300 ppi and it saved at 125mb.

Now, I am thoroughly confused. 

Help?

Bridge Version 10.1.1.166

Photoshop CC version 21.2.3

Camera Raw - No idea, but Creative Cloud says it's up to date

MacBook Pro 2019

MacOS Catalina 10.15.6