I didn't like the story too much, I consider it too pedantic. The author wants to give it more realism or depth by writing dialogues with the teachers about magical theory or describing theory books. In my opinion it makes the story more boring, in the movie or in the books don't tell you how magic works, so in the end it's justo the author giving a speech about what he considers magic. It's a bit like what some Naruto novels do about chakra,It seems the excuse that the author gives to tell you why he is going to learn all the spells si easy, the trick or the key that only the MC has discovered about how magic works, that only he could learn.
Finally, I don't like the MC, I don't know why specifically but I don't like it. I think it may be because it doesn't seem like being Hagrid is of any use. He doesn't have any similar personality traits and I don't see him using his giant complexion for anything either, he's from Ravenclaff, he doesn't like Dumbeldor, he doesn't have a strange pet, nothing. I don't quite understand why he chose that character instead of an OC, if he doesn't take advantage of it. Although all this is based on the first chapters, it may change in the future.