Sounds like Siri - unable to control much of anything on the iPhone outside of reading/sending text messages and setting alarms.
And that’s ok. Those are core features of the phone that absolutely must work reliably and consistently. Far better to do a few important things really well than a hundred things execrably.
It also can initiate phone calls and play music.
And those are really the core use cases for AirPods, HomePods, and CarPlay, the contexts where a hands-free eyes-free interface is most useful.