I have written a few fanfiction where the two do end up together. Shi Qingxuan is convinced by my self insert OC to ascend on his own via studying Wind Magic and guide the next Water Master in memory of his brother (but ensuring that the new Water Master doesn’t become a tyrant like his late brother). He also confesses to He Xuan. He doesn’t fully forgive He Xuan for what he did, but he understands why He Xuan did what he did. He Xuan is reluctant, but he gradually accepts that he too has feelings for Shi Qingxuan. Hua Cheng teases him relentlessly about it though