I liked gongju too, and was rooting for him since the beginning. It's usually the guys who act harsh, they're always the "gentle inside" ones. Sooha isn't bad too, but I know that the nice guys are secretly yandere sometimes.
I just know the only reason Yul likes Seoha so much is because he's being treated gently and with so much kindness for the first time. however as we have seen, this gentle guy has an obsessive side to him and hence continously violated Yul in his sleep. He may not realize it himself, but I think his relationship with Gongju is far deeper and he feels safe with him.
he's by far the best character imo. He's no saint, and I'm not saying he treats Yul any better than Seoha or anything.. but he's been the most forward, honest and true to himself character. and idk, the smallest things he does that show he actually rly cares about Yul in his own ways, I find them endearing. He's not fake. most importantly, I feel like he understands the foundation of his relationship with Yul, and maybe that's why he doesn't change the way he treats Yul in order to not cause confusion or conflict since Yul is so sensitive. I think his consistency is what's most comforting to Yul, even if Yul himself doesn't even realize it. He doesn't push any feelings onto Yul nor has any expectations, but he's always there! like a home/sanctuary. I'm hoping to see their relationship develop further.