"Other" Storage discrepancy

My laptop is a Dell Inspiron 15, with a TB of storage space. After OS and whatnot, C: shows 920 GB of storage, with 322 free, 598 used. I've gone through my personal videos/music/pictures/documents and found only about 67 GB used, so to find out where all of these used GB are I opened the Settings app and looked at my storage, which breaks down like this:

Documents (1.46 GB)
Pictures (5.27 GB)
Onedrive (7.96 GB)
Music (10.4 GB)
Videos (48.9 GB)
Apps & Features (68.1 GB)
Other (424 GB)

FOUR HUNDRED AND TWENTY FOUR GB under Other, and when I clicked on it, it loaded for a few minutes and then told me it can't find any folders to show me. So I did some searching, found some info that told me to make the hidden files visible, then looked again. Now I'm seeing in my C drive Apps, Users, Drivers, etc. But all of it combined comes up to maybe 3 GB, if that.

I have already deleted my browsing history and other temporary files, run Storage Sense to make sure everything unnecessary is cleaned out, and run a Disk Cleanup, and NOTHING has changed. Short of backing up my personal files and completely restoring the laptop, which I don't particularly want to do as I don't think it will help, I've done every solution I can find.

Where is this "Other" storage coming from? What is in it? How do I get my storage space back?