What accommodation options are available for a 3-month short-term stay in Seoul?

Hello! I am soon going to stay in Seoul for 3 months and am currently looking for accommodation. I am planning to enter with a working holiday visa, and although I have considered goshiwons or gositels, it seems difficult due to strict visitor restrictions. In particular, my partner will be staying with family but we are looking for a place where we can be together. I am looking for affordable short-term rental accommodation with basic private bathroom facilities, but goshiwons or one-rooms generally do not allow visitors. Is it possible to find suitable short-term rental accommodation in major areas like Gangnam, Hongdae, Itaewon, etc.? If there are other budget-friendly options that allow visitors and offer short-term contracts, please recommend. Have you had any experience finding suitable accommodation in such a situation? I would really appreciate any advice or information you could provide!