iOS - join audio by default

Whenever I join a Zoom call via iOS, it prompts me to join audio via wifi (the obvious default choice), dialing in by phone, or having no audio at all.  I'm not a Boomer, so I'm never going to dial in to a video call using my mobile phone. Why can't I set up a default audio device? Why doesn't it use the actual device audio by default? Why is "no audio" an option? Surely 99% of users want the first option.