Hello. I am having the exact same issue here. Started today and I have tried everything suggested in this thread and several other ideas without any luck. This is such a disappointment and I am getting really sick of Apples obvious absence in this regard.
it seems like there are many people reading these posts here so as this is one of many forums discussing this issue I will continue following this thread until a proper solution is presented.
Thanks in advance.
iPhone xs, ios 14.2.
Edit: The only thing that has been working for me is by turning cellular data off for about three seconds and then turning flight mode on/off, and then cellular data back on again.