GrapheneOS already runs google play services in a sandbox that doesn’t have core access to the device’s functionality (you can lie about giving apps storage access or location data, for example), and because you already have alternatives to ad-based services (CoMaps, Thunderbird, etc…) you should be safer from telemetry often hidden inside of popular apps like Google Maps.

Nothing’s bulletproof, of course, but the difference with GrapheneOS is that you can see what’s going on, grant permissions selectively to certain apps, or opt out entirely by only installing F-droid apps or using Graphene’s FOSS suite. You don’t have pre-baked telemetry at all, so nothing for them to harvest.