I am operating my phone usually with a BT connection to the car's radio. It looks like the car drops the announcements from pure maps (and also WhoGo maps before) in the case radio or music is running from the car-internal radio.
However, call-related stuff are heard, as the car mutes the radio/music in this case.

It is possible to let pure maps' announcements run in similar mode (higher
"priority", "call-related" or what-ever the mode is)?