i have the same problem. Support asked me to flash the firmware manualy from my computer to solve this issue. Risky and I will loose all the already uploaded and running applications . too bad.! I also wanted to use wifi calls. The support told me that wifi calls are no more available under android ...

It sounds accordingly to BV support that Wifi calls for BV9900PRO running android 10 is not  available and that I have to flash the phone to android 9.
Is this right ? strange