Dimensional Tycoon: I Make Trillions in Every World - Chapter 9: New Custumer

In the current era, people are either normal or are with ‘special abilities’. Cases related to the latter are managed by the “National Anomaly Prevention and Control and Special Species Management Office”.
Qi Zheng Emperor Sheng Lingyuan was reawakened a thousand years later after he jumped off the fiery Red Lake. Xuan Ji, a newly transferred staff to the Reparations Division of the Deviant Control Office, finds himself having to clean up the mess of a revived tyrannical monarch. The two seemed to share something from the past, but unbeknownst to them, a big conspiracy is stirring right underneath their noses that could destroy the balance of the world.

- Description from Novelupdates

Upon transmigrating, Su Xing awakens in a highly advanced game-like martial world.This world is populated by extraordinary beings known as Awakeneds. Favored by Heaven, these Awakeneds can level up and increase their power by clearing dungeons and slaying monsters.Su Xing receives a hidden profession, a Cultivator. However, due to unknown reasons, he is unable to gain experience or level up like other Awakeneds.Unable to level up, he can only cultivate. But in this era of declining spiritual energy, where cultivators are nearly extinct, even acquiring spiritual energy is a luxury. After four years of university, Su Xing is still at the puny Qi Refining stage, struggling to even graduate.Fortunately, he awakens a golden finger, the “Life Simulator,” which allows him to simulate the future by paying energy. He can bring back the cultivation and items obtained in the simulation to the real world.

Hell Ghost Wang Wannian is born again, smiling and proud!
What?
Are you a soldier, will the tank drift?
You are a master, can you give birth to dragons and tigers?
You are a superman, can you call the wind thunder?
Excuse me, I am not targeting anyone, everyone in my eyes, it is rubbish!

- Description from Uukanshu (translated)

The story is about a a hitman, Who dies because of his own recklessness and transmigrates into a game he used to play after his retirement as a hitman.I'm not gonna spoil any further, but i might answer few of your questions.Is MC overpowered?Nope, he'll become strong over time and all battle he'll fight will be because of his effort and techniques.Is there magic and adventure?Yes! It have both magic like normal isekai with adventure and fighting with monsters and many other things. There are other important things like “Essence Stone” But let's talk about it in the chapters.There will be harem?Not really, He will be in contact with many beautiful female and males but one waifu but i haven't decided yet.All i can say is, give it a try, I'll try my best to make it worth your time.