Please make an effort to improve underlying OpenStreetMap dataset:

https://streetcomplete.app - basic task-based, on-the-ground, app for Android

https://every-door.app - intermediate on-the-ground app for smartphones

https://rapideditor.org - AI-assisted mapping in browser

https://www.hotosm.org - task-based mapping in browser

https://josm.openstreetmap.de - advanced editor for desktop

1. A POI/favorites app that maintains a local database with an API for other apps to access it. Apps could then store markers there instead of in their own private db, so that points added on one map app can be instantly available in other apps.

2. A shared traffic data service. Any OSM map app could contribute to the same data, helping reduce Google's advantage in live traffic data.

Obviously, both of these would need privacy protections and be subject to user choice. And there should also be some requirement that both reading and writing be supported, to ensure apps reading POI data don't lock in new data, and to prevent apps reading traffic data from freeloading.