Yeah, a DM shouldn't write a story. The story gets written at the table.

A DM should write a scenario, the concept of a story. With many different NPC, locations, and lore. That can all be moved freely around and only get locked into existence when told during a game.

I call them information blocks. And even though you prepared an NPC block to be at a specific location block. The NPC can be moved to where the players are if the story calls for it. Same with lore blocks, especially if it is something important the players need to know in order to progress. The same lore can be said by any NPC, even if you prepared it to be told by a specific one. Having individual information blocks that switch around gives the players more agency and makes the story more fluently.