There is so much to do in Korea as a solo traveler. The only difficulty you can sometimes face is finding restaurants because a lot of Korean food is eaten together. But, you can always find streetfood or 분식 . I highly recommend going to places like museums and galleries when traveling alone. I think you can focus more on exhibits and reflect on stuff more than when you travel with a friend.
You can also stay at youth hostels. There, you can meet other solo travelers, its great for meeting friends from around the world and you can go out with them when you find something that you can’t do alone.
Hi Bri, it can be difficult but fun traveling solo here in Korea too. I suggest you take a look at some of the tour groups like enjoykorea.asia (IG) for example that offers reasonable group tours with a lot of singles. You may even find some people you would like to travel with.