That's known as the millennial pause. Older generations like millennials want to ensure a communication is working before committing information, while GenZ and Alpha just start talking.
It's named after the pause after pressing the record button while you check it changes shape, but "can you hear me?" is the same thing.
I'm gen Z. You had to start Skype with "can you hear me" because the answer was usually no (via text). I now do that with phone calls because forced bluetooth has made headsets less reliable than before.
On the contrary, older people properly announce themself on the phone, while younger people often don't answer at all, and let there be silence, until the other gives up, and asks who has picked up the phone.
