First short explanation what the App is for:
If you want to do something good for the climate and need a car/vehicle you get a electrical one and charge it with your solar energy.
If you also like privacy, you of course want to use just free software and local monitoring. You dont want to provide any data to the car manufacturer.
The currently only good solution with advanced OBD-CAN support for such electric vehicles this is OVMS https://www.openvehicles.com
The ESP32 based hardware is opensource, the software running on the ESP32 hardware is opensource, the Server the ESP32 device is sending data from the car is opensource. The Android App you use to connect to your local running server instance is opensource.
BUT - you cant get the Android App from the F-Droid store. Its only available at the google play store: https://play.google.com/store/apps/details?id=com.openvehicles.OVMS
Reason for this: Developer think you have to have a gitlab account and you also have to pay to somewhere an annual fee to release a app to F-Droid. Google Play Store would be free of cost instead.
Could some developer help convincing the OVMS-developer that there is no cost or a force to have a gitlab account to release to F-Droid?
Here is the discussion about this: Release on F-Droid · Issue #129 · openvehicles/Open-Vehicle-Android · GitHub