The Harry Potter franchise is another one that I wish I liked better. It just seems like he never gets any better at magic. I mean, does he even study?
Not really, but I think that is part of the draw to the series for me and people of all stripes and ages. Even if he did study, Voldemort had a decades head start. I think it might have been even more unrealistic if he just studied his charms and somehow gained more knowledge than Voldemort and won the day. The story is also about needing luck, needing help, knowing your talents, etc.. I'm not even sure if Harry is the most popular character for those reasons, and why the books were so popular. No, a series with a lot of characters isn't new but it did such a good job of world building and getting kids stoked to read and levelling up as the characters aged through the school years.
I was late fan to the series. Not even sure why, but somebody convinced me to give one an honest read. I read first one and loved it enough to read the next 3 in the matter of weeks. I was at a midnight release for the final book and read it through the night.

I don't really read fantasy besides Song of Ice and Fire so take that all fwiw.