For a domain-specific voice assistant (not navigation, not general-purpose chat), should we integrate via the CarPlay voice-based conversational entitlement, Siri + App Intents/App Schemas, or a hybrid? What does Apple recommend?
Using Siri + App Intents will provide a path in CarPlay, but if you want to utilize CarPlay Templates, you will want to add the CarPlay voice-based conversational entitlement to your project. This will allow you to design an app that uses more than voice and system UI for your app when shown in CarPlay.