I would say not. At least. If he does get strong. It's not because he's just magically more powerful than anyone else but because he earned it.
More like underpowered. The high Demons are constantly cashing those reality checks every time he fights them. What's overpowered isn't his strength. It's his tactical mind. The main reason this guy keeps winning is because he has a habit of outsmarting his opponents. He's not just strong, he knows the best way to use what he has to the fullest.
Intelligent main characters who have genuine competency is awesome.
Guys, will Mc get Extremely op? Or?
Someone spoil me :D