The Witch of the North and Glinda are separate people
Ever notice how, in the movie adaptation of the Wizard of Oz, Glinda the Good Witch is kind of… awful? She was the first person to meet Dorothy and could have told her how to return to Kansas from minute one, but didn’t.
Except! In the book, it was the Good Witch of the North who met Dorothy when she landed, and get this: she’s a totally different character, who was described as a cute, chubby, and grandmotherly old lady.
The Witch of the North didn’t tell Dorothy about the shoes because she actually didn’t know. This one little change from the adaptations makes Glinda a bit awful.
The Wiz, the all-black cast stage musical, gets this right: the two good witches are different characters.
In a mythology as rich as Oz, it’s kind of amazing how little the Witch of the North was mentioned - she never even received a proper name in all of Frank Baum’s work, and was never a major figure again.