[2020] Game crash, Simulation error: Object reference not set to an instance of an object

Try unsubscribing from Building Anarchy.

Can you upload a log from the attempt without Building Anarchy?

You can also try using the Loading Screen Mod to load in Safe Mode. Here's how that's done:

https://steamcommunity.com/workshop/filedetails/discussion/833779378/1635291505029642401/

And then there's Save Our Saves, which is worth trying as well.

https://steamcommunity.com/sharedfiles/filedetails/?id=529129546&searchtext=save+our+saves