The Sims 2 failing to open in the new EA APP ( DirectX 9.0C error )

@blooberryxkrpie Thanks for the screenshot. The settings look good.

Since you mentioned manual Graphics Rules editing, please save these tweaks in GRM once again to make sure the game uses the exact settings listed here. I don't know what you might have edited manually, but even a single typo in the Graphics Rules file will break it and trigger the DirectX 9 error. GRM will override that with settings from your screenshot.

As for Windowed mode, which is one of the possible fixes for the error, you will have to add the -w command into the EA App; for whatever reason, the app ignores any commands added to game shortcuts.
To do this, go to your game library in EA App, click on three dots on The Sims 2 game tile -> View Properties, and add -w to Advanced Launch Options, then save.

After this, try launching your game.

Finally, since your PC has both NVIDIA and Intel Graphics, it would be a good idea to check which one the game runs on. The Sims 2 sometimes has a tendency to prefer Intel Graphics unless you intervene. Once your game is able to launch, go to Documents\EA Games\The Sims 2 Ultimate Collection\Logs and look for the file named something like this: [DESKTOP/LAPTOP name]-config-log.txt. Open it in Notepad and check if NVIDIA is listed under Graphics Device Info.