No the ending is not the same as the kdrama. In the kdrama it ends with him going back to his og body and reflecting on his decisions, then he makes sure to testify against the Jin family for Dojun’s death, and then he eventually convinces his business partner and gf from his life as Dojun that he’s still alive etc. In the novel/manhwa— he doesn’t return back to his og body. His old body doesn’t exist at all. He goes on to live as Dojun. All the plans and investments he made since he was 10 paid off. He becomes one of the top ten richest men on the planet. He marries his college sweetheart that his grandpa had wanted him to get with anyways. He does outwit his uncles out of their shares of Sunyang. He becomes the overall owner of Sunyang and makes it into an even bigger empire. He slowly made sure to build good PR for himself and solidifies business/political connections that his grandpa had as well. He becomes recognized by everyone and even the general public as the true heir to Sunyang who earned it bc the truth of his investments and being the founder of Miracle come to light as well.

The grandma arc
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Dojun promises to forgive his grandma for what happened how she almost killed him. But he can’t forgive how she almost killed his beloved grandpa. HE CRUSHES HER. And it was so satisfying. Bc his uncles try to fight him and protect their mom, it’d very futile though. It was awesome. She basically is exiled from ever returning to korea. She only shows up after grandpa passes away btw. It was very clear she despised him and Dojun.