When I was in my early 20s I had a job delivering pizza. I very quickly learned the delivery area, I knew pretty much every street and alleyway and shortcut to get from one place to another. Much smaller than London but I think the human brain is very good at remembering routes and where things are in an area, as this would have been an evolutionary advantage (go out hunting and be able to find your way back). No GPS, didn't even carry a map with me. We had a large map on the wall at the store, and if I had to deliver to a street I didn't recognize I'd find it on the map, see where it was relative to the streets I did know, and then I never had any problem finding places.
What? In my country at least (France), taxis have been a thing even in the countryside for as long as cars existed (or rather, as long as the telephone has). And I'd be very surprised if that wasn't also the case in most of Western Europe.
In fact it's a much easier job when it comes to routing and knowing your passengers' destinations than doing it in a metropolis.
But in any case, I found that if you want to remember routes, it is far better to study the route before you begin driving, and then not rely on CarPlay altogether. This gives you much higher awareness of street names and directions.
As a bonus you can even set your general location on the mirror for extra accuracy, since the earth's magnetic line directions differ a bit based on location.