Before you start driving, at stop lights, while waiting in lines, etc.

I don't know how it works on CarPlay but when I turn my car on I have a bunch of suggested addresses (home, work, parents, recent Maps searches, etc) that I just touch-to-go. Having to use voice every time you want to navigate not only sounds unnecessary, but cumbersome.

Put in the destination before start driving?

CarPlay does not work at all if you have not enabled Siri. As in it won’t even connect.

You don’t need to enable Gemini or voice assistant on android to use android auto. Some functionality is lost, of course, but you can still navigate and play music.

I almost never use Siri in my car and use a "nav system" every time I am driving.

I set it before I start moving, and then don't touch it while in motion.

I never use Siri when using CarPlay? I’m confused by your question.

I use Carplay all the time and I didn't even realize it has voice control. I just set things up on my phone and drive.

DIt disn’t even occur to me that I need voice control. Stop car. Enter destination. Drive. How hard is that?

Good luck telling Siri to drive to Hronská Breznica. Outside of English speaking countries voice control is very hit and miss (mostly miss)