I've been studying the iOS 15 camera behavior while navigating on CarPlay. It's verrrry different from previous versions. In fact, I'm having a bit of trouble piecing it all together.
It would seem that the SOP for highways now is to remain zoomed in, almost the same level as of local streets. On CarPlay, buildings typically don't show on highways, but sometimes some do. (This could change when CarPlay gets updated.) On the phone, buildings seem to show all the time on highways at the standard zoom. It seems the only time the camera zooms out on while highways is when there's traffic ahead. The camera zooms out just enough so you can see the entirety of the traffic ahead. And then zooms in slowly as you get closer to the end of the traffic. I wonder if this new camera behavior is mainly designed to show off as much detail around you as possible? It's rather unusual for a navigation app to not zoom out while on a highway. Google Maps and Waze do it, as does my car's in-dash navi, and Apple Maps had traditionally always done it. I don't necessarily have a problem with it...I'll wait for the CarPlay update to see how things look with the new details.
On local roads...things seem to be the opposite from before. On the smallest of local roads, the camera seems to zoom out a bit, and buildings don't show. But on secondary roads, the camera zooms out a bit more, shows the horizon, and buildings *do* appear. The camera also sort of behaves like on a highway, where the camera will reposition itself to show off your general direction of travel approaching curves, not necessarily remaining fixed directly behind your car.
I am noticing on CarPlay that the 3D buildings generally appear at higher zoom levels than previously on CarPlay. But there are still inconsistencies compared to what you see on the phone.
I've also been experiencing a glitch where a POI in my "recents" will vanish after navigating there. This has happened twice already. Very unusual. Also, a friend of mine just moved. I updated his address on his contact card. I navigated to his house by telling Siri, "_____ Home", and the directions to his new home came up. But later that day, when going into my recents, "_____ Home" was right there near the top, but for some reason, was now showing his old address.