Sims 4 - Game is Already Running

I have been trying to launch the game for over 12 hours and doing every troubleshooting step I can find. When I try to launch the game, I get the "Game is already running" popup, but then after clicking okay, I get the "prepping game" pop up, that eventually vanishes (crashing I'm assuming?). 

I do not have any mods or CC installed. 

File locations:
EA Launcher - "C:\Program Files\Electronic Arts\EA Desktop\EA Desktop\EADesktop.exe"
TS4 - "C:\Program Files\EA Games\The Sims 4\Game\Bin\TS4_Launcher_x64.exe"
Documents - C:\Users\alyss\OneDrive\Documents\Electronic Arts
 - Note: I don't have OneDrive enabled, I am unsure why that's the filepath
 - Note 2: I'd link directly to the TS4 folder if I had one!!

I installed the game today via steam, and installed the EA launcher as required. One of the steps I have taken is uninstalling from steam and installing via EA. This has not helped. 

I have followed this guide to a T: [CURRENT ISSUE] Sims 4 already running | EA Forums - 11818313
 - When I do the step where you move The Sims file from My Documents, a new one IS NOT created. I can't find any steps to take if this happens. 
 - The game does NOT launch and gives the same error from a secondary local admin account. 

I uninstalled my VPN/antivirus - same issue. 

I added EA and the TS4 launchers to windows firewall exclusions - same issue. 

I ran windows updates, checked my drivers - same issue. 

I've tried switching EA to offline mode - slightly different issue: the same thing happens but I don't get the "game is already running" pop up. Basically, it gives the "prepping game" pop up, and then nothing happens. I watched it in task manager, it just ends task.

Speaking of task manager... TS4 never shows up. Just the prepping game from EA Launcher, and then it vanishes randomly.

I've run the Malwarebytes scan. No threats detected. 

I've run the DxDiag.

Someone please help me, I am losing my mind.