Re: I can't load any of my saved games!
@SunRainKittens When you create a new save with no mods or custom content, and save/quit/reload, can you load that new save again, or has it corrupted too?
Separately, when you load a previous save, do you get a lastexception in Documents > Electronic Arts > The Sims 4? Please delete all current LEs so that if the game generates a new one, its data is completely fresh. You can attach it here as a .txt file if you delete the LE's first line.
Your dxdiag doesn't show any obvious reason for the issue, but that's not surprising given the symptoms you've described.