What procedure/flashing etc did you do please. I’m in same boat, with a v1, iPhone 12 never worked , somehow did last week once, but came back to car next day and nothing.
Format 8GB pendrive using FAF32 file system with default file size.
Download and store the 28.10.2020 firmware from https://github.com/ludwig-v/wireless-carplay-dongle-reverse-engineering/tree/master/Firmware
in the pendrive. (Make sure to rename the file to U2W_Update)
Connect the Carlinkit/Carplay2air to a USB Wall power outlet
Wait for the solid Red light.
Insert the pendrive into the Carlinkit/Carplay2air and wait atlest 4 minutes while the device being updated (You will see alternative red light and green light on the device and finally solid red)
Delete all Wi-Fi and Bluetooth from Phone and Car (then make sure both Bluetooth and Wi-Fi are tuned on in the phone)
Insert the Carlinkit/Carplay2air once the head unit is fully booted.
Select the Phone from the Carlinkit/Carplay2air screen you see.
Wait for the setup to complete