The problem isn't the lack of an explicit confession—his feelings are already obvious. It’s just that Sangho is trying to read too much into Younghwa’s words, because he isn’t used to Younghwa’s direct way of communicating; it’s as simple as that.
They’ll come to understand each other in a few more chapters :3 they are so cuteeeeeee !!!
I love that there isn’t a huge difference in their physiques or height. We’re so used to being presented with a "bottom" and a "top" who look completely different from each other—just to clearly signal what their roles in the relationship will be—but I really like that this difference is barely emphasized here.