@deartwn Why did you install the game into Documents? That is NOT the correct location and is just asking for problems.
Let's back up here. When you play Sims 4, you have two Sims 4 folders with two very different sets of data. One folder contains the game's program files, as in, the data that Origin (or Steam, or the EA App) installs for you. This is the data for the game itself. This folder can be anywhere you want it to be, at least in theory. However, if you put it in Documents, you're risking some serious issues related to how Windows and antivirus programs interact with the Documents directory as a whole.
The second Sims 4 folder contains your user data—saves, saved households and builds, screenshots, etc.—and is always in Documents > Electronic Arts. You cannot change the location where the game looks for this user folder; you can only move the Documents directory itself or use a symbolic link to point somewhere else.
For now, please move the game's program files to a folder on D, as you wanted before. Create that folder on D and call it whatever you want (but NOT Documents or Electronic Arts). Open your Origin game library, right-click on the Sims 4 icon, select Move Game, and choose the folder on D where you want the game to go. Origin will do the rest.
Once you've done that, open Documents > Electronic Arts > The Sims 4 > Mods and put your mods and custom content inside. Then open the game and see whether they show up.