Actualy I'm not 100% sure either, but I think there is a potential GAS.
To the Situation Domain. But isn't the Wealth inequality in this story is more like the subject matter?
It seems to me that the OS conflicts arise from lies, manipulations and problematic thinkings. Examples: The Kim family's daughter manipulates the Parks to fire their young driver, they also convince the Parks that the housekeeper is contagiously ill, so Mrs Kim can get her job. The ex-housekeeper begs Mrs Kim to continue to help her husband survive in the bunker, but she refuses, so the ex-housekeeper becames vegeful. Mr Park hates when one of his charges "crosses the line". The Parks's ignorant thinking about poverty irritates Mr Kim, and when Mr Park expresses his disgusts at Geun-sae's smell, this triggers Mr. Kim to stab Park etc.
I think, the OS Goal is something like playing the role of the Parks's servants, and living together in a compatible way at the same time. It could have been a win-win situation, if the Kims and the ex-housekeeper reach an agreement. The Parks just wanted some competent servants, the Kims wanted financial security, and the ex-houskeeper wanted financial security and security for her husband. I think, it could have been a Success story, if the Kims aren't so greedy.
The perspective of an unrealistic dreamer, maybe? He had an obsession with the rock, which is meant to promise wealth to whoever possesses it. At the beginning he tells his father he does not think of the forgery as a crime, since he plans to go to the university in the next year. Later he images his wedding to Da-hye (the Parks's daughter), in which he will have to bring in actors to play his family. In the end he leaves the rock in a river, but he dreams about buying the Park house for himself and reuniting his family. So he remains Steadfast...
I am not totaly sure who is the IC.... Maybe the father, Mr. Kim? He says: "You know what plan never fails? No plan at all. If you make a plan, life never works out that way...".
I'm also unsure about the RS. Maybe an employer-employee relationship?
English isn’t my tongue language, I apologize for my mistakes.