> ... Porsche said it's going to move ahead with Google Built-In as an interim solution
That's kinda weird as Porsche moved from QNX (say for a 2013 Porsche) to Apple CarPlay (starting from 2017 or something?). If you buy a brand new Porsche today I'm pretty sure it comes with Apple CarPlay.
Maybe this is about more than just the infotainment system?
Yes, from what I read, Cariad is working towards unifying software for many car modules, building a common software platform for EVs / battery management under the VW Group, and creating a platform for DLC / subscriptions capability. It’s more than just Apple CarPlay.
I think you are confusing Android Auto (projection) to Android Automotive OS, which is the infotainment OS of future Porsches.
It doesn't mean it won't be compatible with CarPlay. New Renault cars are using Android Automotive OS and still have wireless Android Auto and CarPlay.
Also Cariad is using Android Automotive OS now (AOSP version), just without Google Automotive Services (Play Store, Google Maps, Assistant).