Switch off the navigation device, disconnect it from the power supply and reset the device to factory settings according to the Garmin instructions. Then update with Garmin Express software.
So I have the Garmin Camper 780 MT-D, don't know what the GMT70 is and didn't buy the latter with it. And the sat nav happily reported a new "road works on the A7" every few minutes on the drive north ;-). However, I don't know whether this came via DAB+ or TMC/UKW. But it certainly didn't come via Bluetooth.
On multi-lane roads and before junctions, the correct lane is indicated by an arrow. This is part of the normal routing and does not have to be specially selected in the options. I am very satisfied with this Camper Navi in my motorhome.
SCHAU MAL HIER:
https://www.garmin.com/de-DE/newsroom/pressreleases/garmin-camper-780-mt-d-der-verlaessliche-beifahrer-fuer-camping-enthusiasten-2858691
https://buy.garmin.com/de-AT/AT/p/570175