I have the same issue. I removed my sims 4 from EA folder and ran the game to generate a brand new sims 4 folder multiple times with different actions taken after it and the game loaded and it seamed ok on first household. Here is everything I tried and the results I got. Please note I regenerated a new sims 4 game after each one.
1. I downloaded the save file that had issues and it loaded then tried to build on a lot and game went into infinite load.
2 new save: played with no adding, played for a while, then tried loading a gallery lot and the game froze (did not put mods in game)
3. New save: downloaded a prepopulated sim save file (recently updated) game worked fine for a while and once again went into infinite load screen when placing a clean gallery lot that had no cc (didn’t put mods in game or cc) also this was not the same gallery lot, but used different ones.
this crashing and loading issue for me started with for rent but became exponentially worse after Lovestruck. Ever since for rent my laptop gets hot. I have a lot of add-ons (usually not now since I’m testing). It’s worth noting I am on a gaming laptop. It’s not like the best but fairly new, and well above EA specs. My theory is that the lots build using TOOL are the ones that are crashing. It doesn’t matter if game has cc or if it’s modded or not. That would have been an easy fix. I do not get errors or LE. My game just doesn’t load lots and keeps loading and loading and loading. I have to force close. I just want you to know you are not alone. I reupdated my graphic card driver. It helped slightly, since some buildings are loading as opposed to none loading. Some people say it’s the ‘off the grid’ challenge. But the save this started happening on empty, created from clean save. Meaning I populated every single lot on every single world. It took a lot of work and effort and I never got to use it. I finished right before Lovestruck patch and the patch destroyed it. Now I am just getting creative and desperate. I switched to dx9 then dx11 and now I am batch fixing all my cc for dx11 because it actually loaded a lot. If you look at the gallery there are a lot of beautiful lots with no cc that people say crashed their game or are corrupted. Since great builders rarely play the game choosing to build instead I think the issue is not related to game mods but rather build mods or build platform. I’m concluding that most likely it’s related to the Tool mod. You don’t need it in your game to use lots build with tool so perhaps the patch did not account for creativity (that would track lol). All EA would have to do is check if lots build with tool (99% of good builds) are crashing. I never use Tool myself but a lot of lots used by me definitely did. If the dx11 change doesn’t do anything perhaps downloading tool will. The problem is that EA will probably update something insignificant that will break your entire save like next week forcing you to once again look for the next issue. When I downloaded Lovestruck patch I did not play sims for two weeks until all mods I used were updated. It did not matter. I seen this issue reported on many websites and other sm so it’s not as obscure as some want you to believe.