Offline map font download.

I am trying to display text on an offline map,

        val textSymbol = SymbolOptions()
                .withLatLng(LatLng(item.latitude, item.longitude))
                .withTextField("TEST")
               .withTextColor(ColorUtils.colorToRgbaString(Color.WHITE))
               .withZIndex(50)
               .withTextFont(arrayOf("Roboto Black"))

this works well when online, but doesn't work at all when offline.

I have added the Font Roboto Black to in the Mapbox Studio. (Fonts -> Upload new font) for my style.
but I don't know if I should also do another action. Like, apply a font to region or zoom levels. (not sure how to do that)

after downloading the offline regions all the maps are displayed correctly but the text doesn't show. (it works well when online)
also, I can't find any downloaded fonts or anything inside the android/data/my.package/ folder or its subfolders.

I am not married to this font and at this point, I would be glad for any font that would display text when in offline mode. tho nothing I put in the .withTextFont() method seems to produce any results.

Regards.

Start with SymbolOptions.withTextFont and the offline region download flow, then reproduce the difference between online and offline rendering using the Roboto Black font configured in Mapbox Studio. Trace how offline map resources are stored and loaded; done means text using a configured font renders after the region is downloaded without connectivity.