iPhone System Data not clearing - Already Erased All Content & Settings

My System Data was using 100GB on my iPhone. I backed up my iPhone to my Windows Computer.

I then Erased all content & settings (as if to prep the phone for selling/transfer)

I then booted up my iPhone and signed into it, but didn't setup from a backup/iCloud/old phone. I figured I would rebuild it from scratch. After getting through the startup process, I checked the iPhone Storage and now my System Data is using 230GB on my iPhone.

What can I do to clear out the System Data?