Monty never opens your door until the end of the game. So Monty opening 999,998 other doors doesn’t give you any information about your door, just the other one

Monty never opens your door until the end of the game. So Monty opening 999,998 other doors doesn’t give you any information about your door, just the other one that remains closed. If you made a one in a million guess the first time, your door has a car. If you didn’t, the other remaining door must have the car. Which do you choose?