I am creating a game where you manage a spaceship, I want a main feature of it to be at least partially accurate gas diffusion that looks something like the diffusion in the game “oxygen not included” except top down.

The game is top down so gas buoyancy will not need to be part of it.
I am making it with Pygame in python, but I am happy to switch to a different programing language if python will be too slow as I want it to run in real time.

I have not yet tried programing it as i have no idea how to start.

How would I implement this?
(google had had almost nothing useful on the subject)