> In my opinion, the most useful next step is to contact Volkswagen support in a coordinated and technically precise way [...] Smartphone: Google Pixel Operating system: GrapheneOS

I strongly recommend saying that operating system is one of "Android" (there are many variants), "Android (GrapheneOS)", or "GrapheneOS Android".

But if you say only "GrapheneOS", you are practically telling VW to respond that they do not support that operating system.