Even if his gokudou skill
only boosts his JoAT skill to a solid B rank, its sheer utility and versatility will out strip many A or even low S rank skills. Especially if it lives up to it's description and lets him gain access to all other skills including elemental and healing spells.
Concept wise the series seems okay. He's gonna balance his his family kindness and generosity with his own ruthlessness.
He doesn't even need to be all that ruthless. Just a fair accounting of their loans would curtail many of the more excessively delinquent and remind the more forgetful of their obligations.
Also with his past experience I get the feeling he will do his due diligence to differentiate the two. So he can make examples of the willfully negligent, while offering leniency to those that are truely struggling.
I assume Gokudo thing is so that he has OP combat ability to protect his family.
While there is an action tag, and the manga description does list jealous nobles among the antagonists, this feels more like the type of MC that outsmart his opponents rather then a straight beat down.