DreamThree
Honestly i don't like the whole modernization and science approach you took with this Harry Potter, The charm of the world was that it was old and mysterious and while i did like you changing up Harry a bit to be a bit cunning I still think you are taking away the magical charm of the world. Now in an earth that is starving for good books and movies i still think it will do good and reach the same level that the books did in our world, it would have been better if you kept the old mysterious vibe. Also I would say not make a very soft magic system for the books but not make it too rigid as well, the harry potter world in my opinion will do well with a medium magic system that still retains alot of the mystery.
So author, let's just make it clear what your MC's plan is. So his plan is to gamble potentially billions of dollars away, because he believes he has better character and world building writing skills than one of the great writers of our time, J.K. Rowling? When he has ZERO writing experience, aside from plagiarizing a couple of screenplays? So he's gonna bet his future and career on a fanfiction, rather than a guaranteed classic? So that's his plan in a nutshell right? And look, I know you're gonna right it to where he succeeds. But that doesn't change the fact that it's not the best of plans. And it wouldn't really realistically work without your MC's plot armor.
I'm sorry to say that Harry Potter isn't actually well thought out. I am happy he has made revisions but he keeps putting all the 'system' works on a pedestal, it's starting to get irksome. Props to JKs success but the HP series is all over the place and there was no overall plan from the start. I'm saying this as someone who's first book series was Harry Potter and is a fan.
At this point it sounds more like he's writing something more like the magicians rather than harry potter but aimed at a younger audience. It probably wouldn't do as well as the original. I can understand pruning up some of the plot holes but not many drastic changes as described without it losing a lot of its charm. Some reasonable changes would be Dumbledore flying his broom for 6 hours rather than taking the floo to the ministry or some other better excuse for why he's unavailable. It's just a weird excuse even if it was a lie. There's a lot of other things that it depends on what direction you want to go with the characters. Like Miss. Wesley's calling out about the platform despite having been to that platform more times than a majority of wizards ever have because of how many kids she's had + going there herself. It doesn't make sense unless you want an undertone of a 'Is this all planned?' On an older reading. Then perhaps some minor things like a matching description of the Leaky Cauldron that is consistent throughout all the books and movies rather than jumping around. I don't think there is much that needs to be changed on story beats just maybe the method they use to achieve the same things. Like how Ron and Hermione get back into the chamber of secrets in the last book because of Ron's spontaneous ability to mimic parseltongue despite even Dumbledore being unable to speak it or understand it despite being a polyglot and able to understand all language. Maybe change it to Hermione using a bit of muggle tech she picked up from home and using a tape recorder or something. It would make sense since she had basically grabbed all her possessions from home before wiping her parents' minds and she's definitely the kind of person to record notes for herself. They could have had Harry say 'open' for them. There's a few 'coincidences' that just feel forced that might have a slightly better foreshadowing since you now know the entire series ahead of time rather than working book to book.