I'm an Android user, but have been considering switching to Apple, and it turns out that you can make GMaps or Waze the default mapping app for CarPlay. I was just reading about it as part of this thread.
“Give me directions to foo using Waze” - gives directions to do using Waze
This might be new, but it definitely works on the iOS 13 beta, although I’m pretty sure it worked on iOS 12. It would still be nicer if we could just set default apps