No sound through hearing aids when having a video call on android

I have ReSound hearing aids, tried them with different android devices, the latest is S21 ultra which has (Direct Android Streaming, a hearing aids bluetooth Functionality), which should be compatible with the hearing aids. When having an ordinary call, or streaming media, the sound comes from the hearing aid, (but not when having a video call in any app, that the sound in this case comes from the phone). May I ask if there is a solution for this problem? My best regards and thanks in advance.