I feel like if you got him in Hogwarts a little faster you probably wouldn't be having this issue. Like you focused too much on wanting it to be different from other harry potter fanfics that your wrote yourself into a corner and got bored.
I really appreciate your style so I hope to see more from you. Hopefully you'll have the motivation to finish in the future but it's REALLY hard when you take on such a large task as this where you have to completely come up with new areas and plot. Good luck in the future!
Really sad you're dropping this novel though, I really liked it. You don't have to drop, you could just leave it on hiatus and only update whenever inspiration or motivation hits? I'd rather have you update like once a year than never