I saw comments on the novel about how it wasn't good compared to the manhwa and thought to myself why?
Based on what you said it seems like Solo Levelling originally got popular for the manhwa, so that clears a bunch of things up for me.
I was looking for an action heavy translated novel and this one caught my eye. For a weak to strong novel that doesn't have more than 300 chapters, I'd say that it is very good.
After finishing the novel I read the manhwa and other than the art style and character design being amazing, it was very bland. Like majority of the plot and characters didn't get a chance to develop properly.
For me the manhwa is average in terms of plot, but I loved the novel. Maybe I'm being biased because I read the novel first and if I had gone the other way I'd think of the manhwa as lacking and the novel as mediocre but I went the way I went. And I like the novel cause its good.