@76c2f5971789a3c1 Please list the full specs of your Mac: everything under About This Mac including the OS and except for the serial number.
Please also list the world you're playing in, and let me know whether you've installed any mods or custom content. It's fine if you have; I just need to know.
Origin is available for older versions of macOS, not necessarily for older models. I believe that everyone running Catalina or newer is forced to use the EA App.
@76c2f5971789a3c1 Pets is the most demanding expansion by a significant margin, and it doesn't get along well with integrated Intel graphics. That's especially true for graphics chips under the 64-bit version's minimum requirement, as yours is. That's not to say you can't play, only that compromises may be necessary.
I'd suggest trying to play without the Pets expansion, at least for now. You'll of course need to create a new save, and please try Sunset Valley first, as it's the most stable of the EA-made worlds. To uninstall Pets, simply drag the EP05 folder out of the "The Sims 3 Packs" folder, which will in turn be wherever you installed the game, perhaps Applications > EA Games. Let me know how the game runs, and we can go from there.
If you really want to play with pets, or at least some pets, it may be possible to work around their most problematic aspects. You'll need mods to do so, and a bit of patience. Let me know if you're interested, but please do test without Pets installed anyway, just so we can see whether the game is otherwise stable.
