I have done less isolation with GrapheneOS than others. I have one profile and that profile has Google Play Services because I have friends on several chat apps, and Signal is the only one that reliably notified me when I got a new message.
Google apps are still in a sandbox.
Location services and other features can be provided by non-Google services.
I know the OS itself isn't siphoning data; With my Oneplus 12 I had to check both Google and Oneplus configs to make sure I wasn't leaking anything.
I can disable network access for apps.
I can limit app access to Contacts and files with "scopes". For example, I have Whatsapp for only a few known people. Whatsapp demands access to your contacts. I can set up a scope called "Whatsapp Users", add only my friends to it, and then give Whatsapp Contact access to that scope.
Google apps are still in a sandbox.
Location services and other features can be provided by non-Google services.
I know the OS itself isn't siphoning data; With my Oneplus 12 I had to check both Google and Oneplus configs to make sure I wasn't leaking anything.
I can disable network access for apps.
I can limit app access to Contacts and files with "scopes". For example, I have Whatsapp for only a few known people. Whatsapp demands access to your contacts. I can set up a scope called "Whatsapp Users", add only my friends to it, and then give Whatsapp Contact access to that scope.