chainful Most of the crashes in your dxdiag are from elements of the Nvidia graphics driver, so please do a clean uninstall and reinstall of the driver. Here's how:
https://crinrict.com/blog/2019/02/clean-re-install-of-graphics-drivers-with-display-driver-uninstaller-ddu.html
When you reinstall the driver, choose the Custom (not Express) install method, and do NOT install GeForce Experience, at least not for now. Its overlay may or may not be a problem, but you don't need it for Sims 3 and can test without it for now.
Sims 3 requires DirectX 9, but if DX9 weren't installed or were corrupt, the game wouldn't open at all. And the Sims 3 errors in your dxdiag are too generic to be of use by themselves.
What world(s) are you playing in right now? You said there's no pattern to the crashes, but do you get any scripterrors before the crashes that might be useful here? The ones that happen as soon as the save loads are usually not relevant, just reports of ErrorTrap doing its job. But if you see repeated errors in the run of play, and especially just before the crashing, that would be of interest.