So I did the full reset and finally things seem to be talking again. I had to do a couple of re-registrations with the app before the car finally started greeting me by name again, not requiring me to accept the terms each time and remembering preferences for driver assist and the meter layout. It seems that things like radio presets didn't get automatically restored and there is a gap in journeys shown in the app between applying the software update and finally getting communications restored. Also a couple of journeys today haven't shown up yet (the last 2 are there, but 2 before that are missing, several others today are then there).