@divaisdancing One of the reasons I asked you to move the Sims 3 user folder to the desktop was to remove all your mods and custom content. It's best to start with a clean folder, nothing at all added to it, and then slowly reintroduce the content you want to use. Even if you're sure your mods and cc are fine, there's no shortcut for testing.
Now that you've established that the game works with no mods or cc, try creating a new Mods framework and adding back only your NRaas mods, nothing else. If the game still works, add a few more mods, and a few more, until you've added them all or found the ones that cause problems. Then you can do the same with your cc. The launcher not opening is more likely a cc problem—mods don't get loaded until the game launches.
As for Steam vs. the EA App, if you own Sims 3 in Steam, I'd use that. It removes the EA App as a possible source of problems, and you can in fact launch Sims 3 through TS3W.exe (or Sims3LauncherW.exe for the launcher) without even opening Steam if you want. This doesn't work in the EA App just as it didn't work in Origin after 2015.
The caveat is that you'd need to own all the packs you want to use in Steam itself; Steam won't recognize anything you only own through the EA App. And you'd need to redownload and reinstall your Store content as well. The way the Store encryption works, items cannot be shared between Steam and EA App installs.