Oh gracious, you’ve reminded me of the anxiety I used to feel trying to get from Otemachi (Mita) to Tokyo Station - with a buggy - in order to get the train to/from Maihama for Disneyland.
My father-in-law recommended it as the best route.
Could never, ever find the underground route and always had to give up and struggle up stairs in order to locate the stations on ground level.
Found I could manage easily by avoiding it altogether and change at Nagatacho then again at Shin-Kiba.
I still get cold sweats thinking about the Otemachi-Tokyo station underground route. Perhaps it was the buggy that took it to 4th Dan.