You can replace the infotainment system, and thus the navigation system. I do have to say that I don’t know how easy this is with all the cars having glorified ipads these days.So in the EU, do they regulate say the navigation systems in cars, so that if you owned a BMW and Mercedes, you could install the same navigation updates and software on both cars?
The first hit on Duck searching ‘replace infotainment bmw z4’ gave me this z4-forum: https://z4-forum.com/forum/viewtopic.php?t=133268