I guess I like the overall premise but I can feel that it is going to be very generic. MC becomes OP with book, then he'll have to fight off the stupid rival who always hates him, his evil siblings for the head of the house position, and finally the evil black tower he is gonna need to take down. This story is trying to be a 3 in 1 deal, and I can already feel my veins popping whenever I'll read this in the future. Also it is kinda funny how the setting switches from fantasy (aristocratic) to modern every once in a while, I get that this is supposed to be a modern magic setting but at least make it consistent with the clothes and building designs.
The mc also is quite a generic protagonist, cheerful and with a sense of justice. But it also feels like he is missing something. A lot of stories, this included, don't show how much children get affected from no longer being a "genius". There is a high probability of such children developing insecurities and a fear of failure or even success (as they don't wanna fall from grace again), and seriously mess with their mental health.
And MC on top of that got shamed by his family and was bullied, yet he is still is a happy-go-lucky guy. Not saying that it isn't possible for someone to be like mc, but it feels fake for him to not have a single shred of self-doubt, and it takes away from the depth of his personality and relatability.