I understand what you are saying. First point is they are making all this big deal about GZY when he wouldn't…
I think ep 10 and 11 were showcases that Ziyu was loved by his father a lot, spoiled to the rotten to the point where his father got a Red Jade Guardian to guard him because young Ziyu needed protection since he likes to play around, weak and sensitive. The episodes makes us learn with Ziyu that his father had high hopes for him to contribute to the Gong family, not necessarily to be a Sword Wielder, but just be a high functioning member of the Gong family. And everyone but Ziyu can see that high hopes his father had for him.
About second point, we are going to probably learn more about Huanyu later so I think there are limited scenes of him. The only scenes we see are of Ziyu thinking of him fondly as a protective and capable brother, so maybe we will learn more that he isn't as righteous as everyone thinks he is, who knows??? And we are probably to deduce that Huanyu was not born from Lady Lan, as Lady Wuji said seeing Ziyu, who is her only child, to be a Gong family member made Lady Lan bitter. So there probably was a first wife/concubine who gave birth to Huanyu and is already dead.
About second point, we are going to probably learn more about Huanyu later so I think there are limited scenes of him. The only scenes we see are of Ziyu thinking of him fondly as a protective and capable brother, so maybe we will learn more that he isn't as righteous as everyone thinks he is, who knows??? And we are probably to deduce that Huanyu was not born from Lady Lan, as Lady Wuji said seeing Ziyu, who is her only child, to be a Gong family member made Lady Lan bitter. So there probably was a first wife/concubine who gave birth to Huanyu and is already dead.