Hi, I'm David an independent advisor and user just like you. I'll do my best to help you with this.
It looks like this "UserData" folder may have been set-up manually at some point. The location of the Documents, Downloads, etc, folder can be moved from the default location you mention for any user of the PC to any other location.
If you right-click any of your standard folders in this "This PC" view, go to Properties, then look at the Location tab you'll see the actual folder where they are being kept.
Regards,
David