My missus has been having this very issue since she updated her iPhone XS Max to iOS 14. Tried wiping the phone and reinstalling the iOS from scratch but it didn’t help at all. Resetting the network settings did nothing either. This is EXTREMELY frustrating.
Can someone from Apple please take a look into this? Most, if not all, of us didn’t have this issue prior to updating to iOS 14 so it can’t be our handsets.