Entire Sims 4 Documents Folder Reset

@SargentSuccc  It's unlikely the Desktop App would have affected your Documents directory in any way, and it certainly hasn't messed with any of my games' user folders.  The more likely culprit is OneDrive, so if it's running on your computer, please check in its version of Documents for any stray Sims 4 files.

If you don't find anything there, you can search your hard drive for the files.  Open a File Explorer window, click This PC in the left panel, and type Slot_ in the search bar in the upper right corner.  This should turn up any saves on your computer.  If the search turns up any saves, click on one, click "Open file location," and you'll land in the folder where your saves are.  Your other content may be there too.

In either case, you can move the stray files back to Documents\Electronic Arts\The Sims 4, and the game should read them again.