

There’s nothing wrong with the magic system because there’s always a reasonable setup and payoff for what can be done with magic and solutions never come out of nowhere as some deus ex machina. The magic system the stories had worked perfectly fine for the stories that were being told. Not every magic system has to be some stupid overly explained BS that takes all of the actual wonder and “magic” out of it.
Rowling is a piece of shit terf but you Sanderson cultists are still so fucking annoying. There’s more to magic in storytelling than just the exact, specific mechanics of how it works. Read Earthsea.
Rowling was writing about grade school kids going to school. Grade school kids get bored at school. If they live in a world where everyone uses magic and it’s not that special they’re going to get bored of learning about magic sometimes. It’s like if in grade school our teachers spent a bunch of time teaching us how to use computers, phones, and other technological devices. Sometimes it would be cool and interesting and a lot of the time it would be pretty damn boring.
Plus Rowling wanted the grade school kids reading her books to relate to her characters, so she gave her characters a schooling experience they could relate to. And as much as I hate Rowling, there’s something inherently kind of comedic about a bunch of kids being bored silly learning about magic because it’s something that seems like it should be exciting to us, the reader.
The boredom of the characters isn’t a failure of the writing or magic system, it works perfectly well for its intended effect.