MC has a gritty, dark and painful life that leads him to trust nobody.
And then he meets mc npc protaganist two, whom he revers as his idol, a beacon of hope within the chaos. And helps him.
The op cheat like hero is the protag people of a manga people usually dislike, used by others. Too powerful for his own good, kinda stupid but honest. A good person but misguided.
And the "ntr" mc is there to support him from the shadows, it's almost wholesome.