@patroclox : In an earlier post, you wrote that you see the message "Navigation is disabled" when you switch to NAV.
I think the wording here is important, as is the behaviour of your MMI system prior to the message.
When you first turn on the MMI system (ignition OFF) and switch to NAV, after initialization, you should see a map on the display for a brief time (seconds to minutes), until the message "Navigation database is blocked" or something similar for 3G High systems. This suggests a problem with the so-called "activation".
If, however, when you switch to NAV you
immediately get a message that "Navigation is disabled", that's usually a different problem (possibly related to settings in the Green Engineering Menu).
If the problem is that the the nav database is "blocked" due to "activation", refer to this recent post:
MMI 3G navigation 6.30.1 Europe - currently 2020
In his case, he re-installed K0257_D1 as a user-defined update in the Red Engineering Menu initially.
In any case, you should post a picture of the screen that is telling you that "Navigation is disabled" to confirm. --g