Open source Map libraries/SDK

I am in the process of adding some map based features to my React Native application. The quick and easy solution will probably be using leaflet in a webview e.g. with react-native-webview-leaflet. However there are a couple of problems with this approach that I don’t like. A html file that has the leaflet javascript embedded in it has to be loaded into the webview then the map is controlled by injecting javascript into the webview through an inject method. It all seems a bit clunky.

I would rather use a native map Activity than a webview, e.g. react-native-mapbox-gl/maps which uses the Mapbox Maps SDK for iOS and Android. The problem with this though is 2 fold. A Mapbox account token has to be configured in the SDK and horror of horrors the SDK sends telemetry back to the Mapbox service.

So my question is are there any open source map libraries that I could use instead of a webview or Mapbox SDK?