You seem to be greatly misunderstanding what is actually happening.

You are conflating default OS domains with google play services. Google play services is not bundled or installed by default, and is not given any kind of privileged access when it is installed. It does not handle OS domains or functionality, and GrapheneOS does not proxy its connections in any way.

As for the default domains of the OS, most are to GrapheneOS servers, not proxies. The only default OS connection that is proxied to google is remote key provisioning.

As for non-default connections, the only google proxies are widevine, for apps that use widevine, and SUPL, for location locking. SUPL can be disabled, and GOS is considering removing SUPL if network location is effective enough, or if they can host their own SUPL server viably.

https://grapheneos.org/faq#default-connections https://grapheneos.org/faq#other-connections

These connections do NOT contain identifiable information. That is false.

Note RCS chats are also not proxied.