that's why i appreciate brandon sanderson because he was sort of one of the only writers that really cared about making magic systems explicit and logical. redditors would say "but it's magic it doesn't have any rules by definition" but honestly, when a magic system doesn't have coherent rules, it's just lazy writing. harry potter universe is so dogshit at this, they have time travel and luck potions and god knows what and magic basically works whatever way JK Rowling needs for the plot to work. people enjoy HP for the characters, more than the world building.