Revenge.
I want a real MC who isn't perfect who is wronged. Then I want him to get revenge. But as he gets revenge, I want him to go too fat so someone else seeks revenge.
Also, I want the original assholes to have gotten away with the revenge long enough to regret it and try to fix things, but never get a chance to say they are sorry or show they made up for it when the MC gets his revenge.
Later when the new person who wad hit with collateral damage from the revenge tries to get his revenge, I want him to reveal to the MC that the people he got revenge on were sorry and wa Ted to fix things and then show how he wronged an innocent and that now the new person is here to get revenge.
And the MC should now regret their revenge, but they can never fix things with those he got revenge on. He should then try to fix things with the new person seeking revenge on him, but they are so angry they won't accept it, so he winds up killing the person and they never get their revenge.
Then that person's death should drive someone else to suicide. So not only did the MC get revenge on someone trying to make it up to him, but he should accidentally harm an innocent and the person trying to avenge the innocent should get killed thus causing the innocent to lose all hope and kill themselves.
Then the MC's supporters should cover everything up and tell him for the good of the kingdom or some shit, nobody can know.
So the MC WINS, but must live with knowing what a total monster he is and that he will never be punished for his crimes. No matter what he does, he can never fix the damage he caused, and realize the original BS that caused him to want revenge was a lie and if he had just let go of the pain, he could have been happy, but now he won everything, but is alone.
And then maybe he gets isekai'd into a harem with big tiddy bunny girls.