Is this true for Maps and most critically Voice Assistants?

How do I get Siri to navigate using Google Maps? How do I replace Siri with a different voice assistant?

You can't for either of those questions.

Nevermind that changing the browser doesn't actually change jack because Apple doesn't allow competition in the browser engine space.

All in all, it is just hard for me to take seriously an opinion saying that Apple allows for unrestrained competition on its devices and Microsoft is the big bad in this space. Historically, maybe true - but not even close to true now imo.