That's a pretty good summary. There are many different sets of approximations and simulation techniques that make different trade-offs of accuracy/scale. They'

That's a pretty good summary. There are many different sets of approximations and simulation techniques that make different trade-offs of accuracy/scale. They're essentially using outputs of a higher-fidelity model to tune the free parameters of a lower fidelity model, and using ML to explore the parameter space efficiently. The higher fidelity model is itself still an approximation, but there's a lot of interest in this approach and quite a few groups doing work like this targeted towards various material properties, since there just isn't nanoscale experimental data to train models that depend on nanoscale material features.