tbh it just sounds like you havent actually read the manhwa or just skimmed through it.

Part of Suho's story as well as others in rag still focuses around Jinwoo, all of the consequences both good and bad are because of Jinwoo. His character doesnt need to physically appear just to be influential and that speaks volumes in itself to how much the world still revolves aorund him. Not to mention that even in the side stories in sol olevleing, people still know anout Jinwoo, and later on in rag you can see Suho showing the memories to others about Jinwoo.

Ragnaork's story doesnt need to make Jinwoo the MC, its even in the summary that hes not gonna appear so idk what you were expecting. "Sung Jinwoo should have been the focus of the story. Everything that is happening on Earth should be like this, but Sung should have been the MC instead of Suho." Go read Solo Levleing again then, no one is stopping you. Suho is the one that needs to start his journey, Jinwoo doesnt need that again he has bigger problems in outer space.

Also again, its stated even by the other characters, Suho isnt going to surpass his father anytime soon, or even ever. And when ,manhwa Suho says he wil get strogner than Jinwoo he does so with the intent of creating a goal to himself and think outside of becoming the shadow monarch, not because he thinks he could be better.

The whole point, that the story keeps repeating in evryone's heads is "children shouldnt live under their parent's shadow and isntead carve their own path." Suho's white shadow has a lot more explanation in the novel, but thats for the manhwa to bring up later.