Nirvana in Fire 2 | What was that??

I watched NIV1 and was super impressed. It is one of my fav cdramas now. Then I got to know they have sequels too. I know that NIV2 didn't have the same actors(for obvious reasons) and that the story is completely different, it's regarding the grandkids. So I never went in expecting it to be as great as NIV1.

Okay I did like the drama, it wasn't boring, had good pacing for the plot I would say. But what was it 'actually' about? I am not expecting a revenge plot of sorts like part 1, but atleast it was suppose to have a general strategy about the story right? Every story has a main character (about whom the story is about or revolves around) and the story progresses along. But what was NIV2 thinking when they made the MC disappear for about 10 eps straight? Like he didn't have any contributions as such to make. Like what really happened? Did the actor suddenly decide to not be part of it anymore? Or is Xiao Yunqi the main character? -_-
Up until the plot was revolving around the Changlin mansion, Puyang Ying, and court politics, it was exciting and going good. And then Xiao Pinzhang dies T.T I was sobbing like anything in this part!! And then another heartwrenching incident. The father too dies! Shit. These two incidents made me cry my eyes out. Until this we see what the story was supposedly about (a young guy who's carefree in nature, grows about to shoulder responsibilities. A coming of age story you say). Then they leave the capital, and boom! he just disappears from the screen almost completely. Once or twice I heard "pinjing" "lord changlin" being mentioned/referred, he sends a letter to the prime minister (yeah I get it). But this wasn't enough! Episode after episode it was just Xiao Yunaqi and the court and donghai and etc etc. Where is our main character?
Only after half of ep46 he is seen coming to rescue "peesha" and then done. I did liked the ending, our MC gets his happy ending with his fated mate. But this drama did not have that desired impact! Even the final showdown was meh.
IDK why the production or writers decided to take the drama forward in this manner? Another thing, if it's the same production and this is made as an official 'part two' or 'sequel' of NIV1 then why are the same actors repeating lol. So many actors are back here. For eg: Someone who died as traitor in part1 are back as a doc. I understand if the production is different, but they were literally showing flashbacks from NIV1 then how come they did this! Also, Lin Xi -_- the most boring character! IDK if her character itself was written like that or it was the actress, but everytime she's on screen it screems "boring"!!
I am done with my rant I guess lol. But all in all, I did like it, did not hate/disliked overall. I think it was interesting up until we had Xiao Pinzhang, I was really missing him. I also liked the family dynamics of the changlin family. Father, elder brother, sis-in-law and lil bro. So wholesome! I could really feel the emptiness in the end :(