I am looking to program something similar to a simulation game, but free-form in its customization and scripting to the point where no strategy game will get me close enough.

I initially thought to start from scratch, simulating all the basics. Simulating money, people, resources, maps, etc. Obviously this is very ambitious.

Are there any libraries or frameworks that could help me with this? I don't want something opinionated that decides the model for how to simulate, for example, money or a person. I want to preserve the ability to simulate those with the models and math of my choosing. But maybe a library that has the foundations of simulation in general, so that I don't have to build everything completely from scratch?

I understand what I said sounds very vague. This will be something I will discover as I do more of it, so forgive the vagueness.