I've uninstalled everything and just installed base game, but I'm still having the same issue. The game seems to be permanently broken. Because the graphic levels are so low, I get really good frame rates but the game is unplayable because there are still huge black shapes in the middle of lots and floors missing. With just base game installed, I can load lots temporarily, but going into build mode or trying to save crashes the game. With the other packs installed, it crashes as soon as a lot is opened.
Thanks for the link, but I'm struggling to find live chat support. I've only been able to find a way to message them (but yesterday I saw something that said you can report a bug but you won't get a response). Is live chat only available in certain locations or am I just missing something?
All the Apple troubleshooting revealed no issues with the graphics card and my system, and I've been able to play another game with very high graphic settings, so it seems to be an issue exclusively with the Sims. I can see that these issues are only affecting people with the 16" MBP, but if the laptop has the minimum specs provided by EA, then they should be finding a solution to make sure the game is compatible with the technology. Otherwise, they should advertise that the game is not suitable for people with certain laptops and we could save our money by not buying the games in the first place.