CarPlay and iPhone apps - Dual use?

Thank you for finally adding Waze to CarPlay. As an Uber driver, I find that Waze is a superior navigation system as opposed to the native Uber app. (Sorry, but your Maps app doesn't connect with Uber as an alternative navigation system, or I could use it.)

However, it is rather irksome (and somewhat dangerous) to have to keep switching back and forth between whatever CarPlay app I'm using (Music, navigation, Podcasts, Audiobooks, etc.) to the main CarPlay screen, then having to tap the Uber Driver app to access it.

My question is: if the driver is using CarPlay, can the CarPlay system/screen control the apps that are currently on CarPlay, and can the iPhone keep open the app that is "live" on it's screen, instead of CarPlay mirroring the current app on the iPhone screen? For clarification: I want to use a nav app on the CarPlay screen, and I want the Uber Driver app to stay visible on the iPhone screen.