Shen Yin Wang Zuo

I heard it's one of classic oldies. Might as well try it out

And I thought that it would be different from other wuxia/cultivation novel, but sadly it falls in the same trope as the others. MC's in this trope starts as genius then kinda being rushed to become powerful, taking risk everywhere, then finding power ups in impossible scenarios. Taking risks way below the min level & killing enemies way above hsi level, specially impossible feat. I thought there'll be time skip to give MC growth, but sadly it's the same.

anime is fantastic if you also liked soul land. It's called Throne of Seal. Although it's a lot of fighting scenes...  you gotta like that, and of course MC becomes powerful rather 'quickly' but got his team and his love interest that he continually hangs out with. Similar like Soul Land basically.

hows the romance here? is there any harem?

This is a common issue with the author's series. All of his characters must reach their pinnacle before 30 years of age. He simply cannot transition a MC into an adult (family, children, higher responsibilities). He needs them to become a god or something similar so he can cut the story before he has too. Its writing style isnt half bad but he fails to structure a character's growth well.

This guy should probably learn from Gu Zhen Ren