Mods and Saves Gone

Have you pressed "load" rather than the play button?

Are the mods enabled in the options menu?

Yes the only game that shows under load game is the one they made me create to get started with the Sims. My mods are enabled in the options menu but when I press view custom content it says there is nothing there.

@Talia_Simss  Please move your entire Sims 4 folder out of Documents\Electronic Arts and onto your desktop.  Launch the game to create a clean folder; you can quit at the Main Menu.  Go into the saves folder inside the old Sims 4 folder, highlight your saves, right-click and select Copy; then open Documents\Electronic Arts\The Sims 4\saves, right-click in the blank space, and select Paste.  Launch the game and see whether your old saves show up.

@Talia_Simss  You moved the game's program files, as in the installed game itself, not the user data folder.  The user data folder is always in Documents\Electronic Arts; if the game can't find one there, it creates a new one.

Please move the Sims 4 program files folder back to Program Files (x86)\Origin Games.  Then go into your Origin game library, right-click on the Sims 4 icon, and select Repair.  If Origin still thinks the game isn't installed, let me know.

@Talia_Simss  Okay, what's in OneDrive right now?  Please take a screenshot of the contents, or at least the contents of the Sims 4 folder(s) in OneDrive.  Let me know whether the game downloaded fully again or not as well.  The easiest way to find out is to see whether you can actually play.

Yes I can actually play and I included the contents in the Sims 4 folder

@Talia_Simss  Okay, that's a copy of your Sims 4 user data folder, not the program files.  You can prevent OneDrive from auto syncing the contents of Documents:

https://support.office.com/en-us/article/choose-which-onedrive-folders-to-sync-to-your-computer-98b8b011-8b94-419b-aa95-a14ff2415e85

Launch the game once, to make sure all your content is still present.  If it is, you can just delete the Sims 4 folder in OneDrive.  If your content isn't showing up in-game, you can replace the folder the gme is using with the one from OneDrive.  Open a File Explorer window, click on This PC in the left panel, then follow this path:

C:\Users\[your username]\Documents\Electronic Arts

Move the Sims 4 folder to the recycle bin; don't empty it yet, in case it turns out there's something in that folder you want.  Then move the Sims 4 folder from OneDrive to the Electronic Arts folder in the path above.  Open the game again, to make sure all your content is back.