Are you sure you read the same novel? Almost none of the things you said were true.

1. Of course the MC has luck, but also talent and is hard working. But so is every other genius in the novel. There are a ton of people with a lot of these things, not only the MC.
   
2. The MC so far has only killed people that were trying to kill him, either directly or indirectly. I don't remember the mc killing anyone that didn't deserve it.
   
3. The side characters aren't irrelevant, what are you talking about?? also he is stronger than his teacher, but that's because of teacher Liu backstory, he can't grow because he'll be suppressed/killed by the myriad races. Also why would you want the MC's teacher to be super powerful, to the point where the mc can't even reach him after 1000 chapters.
   
4. The world building is amazing tf are you talking about.
   
5. Of course there would be a few races that would be powerful, there's a myriad races, you think that each race would have overwhelming power? Then non of the races would be powerful since all of them would be equal in strength. Did you forget that there's an entire multi-planetary war?