Re: Stumped on what CC/Mod is causing game to crash?
In addition to what @luthienrising suggests, you might want to take a look at your build/buy CC in Sims4Studio (S4S) to see if you can spot the problem file(s) that way. You might be surprised at what you find. I know I was when I did it for pretty much the same problem a couple of years ago. I found a slew of problem files that I ended up removing. And my game runs a lot better than it did before and loads faster as well.
You might find a few things you have aren't even showing in the game catalog. I did. The objects were broken from day one and I never realized it.
Take a close look at anything that was created to add recolors to a game object. Make sure you look at all the recolors to make sure they actually show too. But tbh, a standalone item is more likely the problem. If you have things like default replacements that add slots, those won't show in S4S but could be broken. Test those in a throwaway save to see if they actually work. And that goes for anything you have that doesn't give you a visual in S4S. Some broken items simply won't show up at all there. If you don't have all game packs, it could be something where the creator used an item as a base object from a pack you don't have. As such, the item will probably not show up in the catalog at all or show up distorted, give you a thumbnail that is messed up or just disappear when you try to place it on a lot. Walls and floors typically don't give problems but again, just make sure they work.
One thing you might want to consider is reducing your build/buy CC. If you're like me, I tend to use the same items over and over again and there were lots of things in my mods folder I used once or not ever. So, removing things like that has a lot of benefits - less to go through when you have a problem, and the game loads faster and runs smoother has been my experience after cleaning out my CC, both build/buy and CAS.
Another thing you can try is reducing your graphics setting down a level. That will decrease the detail of distant objects you are able to see in the game from a lot. You'll probably need to experiment a bit to find settings that you like. One more thing you can try is trying a custom GraphicsRules.sgr file. There are many out there so try a few and see if you can find one that stops the crashing but is to your liking.
Hope this helps.