It’s interesting that you bring this up. My family had a lot of Korean friends in Moscow. But most of them were already third generation Koreans and most didn’t learn Korean, because of their parents decision against it.
My mother’s friend, a third generation Korean, a geopolitics professor was complaining how South Koreans who work at the embassy in Moscow treat Russian born Koreans as second class citizens. But I guess that might be just her personal experience.