Is it difficult for foreigners to find a studio apartment in Gangnam these days?

I am a foreigner looking for a one-room apartment in Gangnam. After a long time, I checked rental apartments through Naver Real Estate, but the real estate agents in popular areas were very unfriendly during phone calls. When I asked about a property and said, "Please let me know if any other properties come up," the agent laughed at me. When I asked why, I was told that many people are looking, so I should look for myself. I remember that real estate agents used to genuinely try to help, but these days, that doesn't seem to be the case. Additionally, finding an apartment itself is difficult. Nowadays, there aren't many listings, and most are only available for sale or jeonse, so I have a lot of concerns as I want to live on a monthly rent. Is there a shortage of rental apartments these days?