What I experienced is that there is a limit to what can be successfully simulated. The higher the precision gets, the larger the number of dirt effects will get that do play a role in your design. It is very instructive to see how really precise (7 1/2 and 8 1/2) digit multimeters are built.
Just have a look there at component selection, PCB design , thermal management, aging, drift, shielding, EMF, thermoelectricity, triboelectric effects, hysteresis, ...
I have never seen a model that takes all these effects into account. For certain effects, only heuristic models are available (Arrhenius, ...).
It is probably fruitless to build a complete, successful model of a very high accuracy ultra high precision circuitry taking ALL relevant effects into account. Some effects can be handled heuristically, without a complete theory behind it, and the heuristics can still be useful.
Conclusion: A well handled bag of tricks can make your precision elecectronics design life a lot more easy. If a consistent theory is available, you dont need the tricks anymore, but at cutting edge technology we are quite far from this situation.
So, the search for exact models and deep understanding is fine, but pragmatic solutions are OK too, as long no established and general theory is available.
It is like the old Aristotelian saying : The Perfect prevents the Possible.
Enough of philosophy, get back to your benches, measure, research, model and create better a better understanding. In the meantime, some (plausible) tricks are OK. The final result is what counts.
Regards
Wolfgang