I just got a 16 inch MacBook Pro a few days ago. Intel Core i7, 16 GB Memory, 500 GB Hard drive, two video/graphics cards: AMD Radeon Pro 5300M, and Intel UHD Graphics 630.
After downloading all the packs I own (all expansion packs, all game packs except Batuu, all stuff packs except Moschino and Fitness), I launched the game and none of the rooms had floors. Neither Build nor buy. It looked like a reflection of the sky or of the walls. I tried toggling edge smoothing, Retina display, vertical sync, laptop mode, lowering graphics settings to the lowest setting. After that didn't work, I went to the energy saver settings and disabled automatic graphics switching. That still didn't work, so I downloaded gfxCardStatus, which allowed me to use the discrete graphics card only. This solved all graphics issues! Huzzah! Except then the game crashed. I repaired it, except Origin only repaired the base game, not the expansions. I noticed all my packs said "Finalizing". I downloaded the Reset Origin tool, reset Origin, then reinstalled it. Okay so now my packs say "Play" instead of "Finalizing", great, except now when I play it still lags a lot and the latest issue is the "Red Screen of Death". I'll be playing and the whole screen will go red, the game becomes unresponsive, I can't Quit out of it, so I have to Force Quit. I was just on the phone for an hour with someone who tried very hard to help but this issue is persistent and nothing seems to work.
In short: The Sims 4 is just unplayable on the 16 inch MacBook Pro, and since I love this game and spend a lot of time on it, I'm seriously considering returning my brand new computer and just sticking with my old one. If you want to play the Sims 4 and are considering getting the 16 inch MacBook Pro: don't!
If you can think of other steps that I can take that might help with this issue, let me know and I will try but I think the issue is the computer.