CarPlay is a nightmare for many because its premise only considers 2 options: use CarPlay, don’t use CarPlay.
If you want to mix and match features across what your car offers and CarPlay offers (e.g. use Podcasts app but stick with native navigation), the UX starts to breakdown very quickly.
No, this scenario works fine. Car audio (and UI) can interleave with CarPlay. I can put podcasts on my center screen, my car manufacturer's navigation in the driver's screen, and the navigation prompts will duck the podcast and interrupt as appropriate. This isn't hypothetical or hard, my car does exactly this today.
If you want to mix and match features across what your car offers and CarPlay offers (e.g. use Podcasts app but stick with native navigation), the UX starts to breakdown very quickly.