beaconDB is a drop-in replacement for MLS, which uses the same format request that’s used by Mozilla’s Ichnaea.
The source code is available on Codeberg: https://codeberg.org/beacondb/beacondb
You can contribute to the project by using an app like NeoStumbler (GitHub) or Tower Collector (GitHub) to submit location reports. NeoStumbler does Wi-Fi, Bluetooth and GSM, while Tower Collector can only do GSM cell towers. Both are FOSS and available on F-Droid.
It is also recommended by the GrapheneOS project: https://grapheneos.social/@GrapheneOS/112759509558471713
https://grapheneos.org/articles/positon-location-service
Just keep in mind that it’s still in relatively early development, which is why it really needs contributions.
So, you are willing to give your location to Google anytime any app asks for the location permission? A lot of people is not. And there’s been efforts over time to get privacy-friendly location services. So there’s clearly demand for this, even if it’s still niche due to lack of knowledge.
No, I don’t share location data with Google. What gave you that idea?