Since switching to a smartphone, I can't count the number of times an app or notification has engaged and prevented the proximity sensor from blocking screen input, causing my ear to tap something, disrupting the call.

I also can't hear well (or be heard) without speakerphone on regular calls because the handset speaker is small and hard to align with my ear, and the max volume generally isn't sufficient to overcome ambient noise. Related, Teams noise cancellation also suppresses my voice if there's a low rumble in the background, like air conditioning.

Using speakerphone with the volume lowered is usually the only way I can reliably make and take calls.