My airpod pro doesn’t switch between iPhone and iPad Pro automatically

I just purchased AirPods Pro but it doesn’t switch between iPad Pro and iPhone 11 Pro automatically. I have to manually switch it. It doesn’t connect to both devices simultaneously. It disconnects one device when the other one is in use. The only reason I bought this is to listen to conferences or talk and answer phone calls without much interruptions. I even updated both the softwares but still doesn’t switch automatically