Blacked out walls, floors and sims

I'm getting a similar thing. It blacks out some walls and floors, but also some objects too. The first time it happened I copied my family to the gallery and started a whole new save which was really annoying as I'd worked for months curating gallery builds to redo my worlds.

It happened again yesterday. It seems to be my more elaborate builds with more objects in. I guess the game just can't cope with too many which I think is crazy because why give us big lots if we can't fill them up without issues? When it happened yesterday even some of the surroundings were blacked out such as parts of the road external to the lot. I tried loading other lots in other worlds and one in the same street and there were no problems with those, just my main house. I quit without saving and when I reloaded the game I moved my family out and built them a new house is a less populated area with fewer floors and rooms and so far so good.

I'll also mention that I've had issues with the game crashing on the lots that are having issues too. So it's either the game crashes before the house finishes loading, or it loads with things blacked out.

I'm on console so it's not a mod/cc issue.