@jazzmiint Strange, I can always see my game library even with Origin in offline mode. If it's not working like that for you, that suggests that something else weird is going on with Origin.
Regardless, you should be able to launch Sims 3 directly from its .app in either Applications or Users > your username > Applications. It should work both if Origin is already running and if it isn't: in the latter case, you'd see the Origin sign-in window, but once you input your credentials, the game should load.
I seemed to somehow fix seeing my games in offline mode of Origin, yet when clicking play and opening the Sims 3 Launcher I am met with this message (in the screenshot below) and when I click the play button, it takes me out of the launcher back into the Sims 3 page in my game library where the option to open the launcher is. If that makes sense. I also tried on a different admin user and got the same issue 5 minutes into the game, no change in graphics or any settings (aside from removing the interactive loading screens which I usually have off anyway) and still had the frozen game but the option to click around in the background.
@jazzmiint The error is unsurprising given that the launcher tries to load ads and other data from the internet. But that shouldn't prevent the game from launching at all.
If the game is still working in the new user account, try turning all the graphics settings down to the lowest options. (Change the settings at the Main Menu, then quit to desktop before loading a save.) I don't think you necessarily need to play like that; the point is to see whether you can get things stable and then build from there.
Going by the launcher in your screenshot, it looks like Pets is still active. The pack shouldn't prevent the game from launching either, but it certainly could cause the freezes.
