The screenshot is taken after 1s of simulation as it's a static simulation and no dynamic simulation. The boundary conditions are basically the heat-radiation to the ambient air, LN2 inside and the 500W load.
As you said it's way too difficult to do a 100% correct simulation. The biggest problem is that LN2 is not cooling down steady. The temperature coefficient between the LN2 and the copper is the biggest problem here. Decreasing the temperature of the pot the temperature coefficient is increasing. So it's impossible to do a simulation e.g. of how long it takes to cool down the pot or to measure the temperature you can reach.
But you can clearly see the heat transfer inside the design which is enough to see whether a hole is placed at a wrong spot or which mass actually helps as a buffer.
Yea I can decrease the thermal radiation from the ambient air which will make the pot appear in a deeper blue. Ofc it's more realistic with insulation but this way you can see the thermal transfer a lot better between load and LN2. It depends on the insulation material you're using. Using the real armaflex it helps up to about 14mm thickness. You will just need less LN2 but the performance of the pot won't change.