Thank you for your continued support. The POCO F7 Ultra has undergone strict professional inspection before leaving the factory, so you can feel free about the performance and reliability of your device, knowing that it has been thoroughly tested for quality and functionality.
The problem is that the car disconnects the connection initiated by the phone, causing the call sound not to go through Bluetooth. If you want the ringtone to go through the car, you can go to the [Bluetooth] interface >> [Additional settings] >> turn off the simultaneous playback of incoming ringtones.
Does it help?