Magic Earth: Privacy friendly maps with turn-by-turn navigation, OpenStreetMap, Crowd-Sourced Traffic, 3D maps, Satellite maps, Offline maps and Transit.

I have GrapheneOS and recently tested Magic Earth and Organic Maps, in my rural area around town. For me, MagicEarth audio worked fine, but Organic Maps was mute..

Magic Earth found specific street addresses better than Organic Maps/OSM, but couldn't list street names, just like OSM.

AFAIK, this is because Graphene prevents the downloading of the Google voice modules that have access to local street names. I could be wrong on this.

TLDR; You can't. GrapheneOS prevents it because Google owns the voice modules including the specific street names and most privacy invading maps software tracks your location in order to vocalize the basic naviation and street names.