There are actually quite a lot of people that use GrapheneOS as a hardened version of Stock Android.
On GrapheneOS pretty much all Android apps work perfectly fine with Sandboxed Google Play with just a few exceptions:
- Google Wallet/Pay (requires GrapheneOS to be whitelisted by Google)
- Android Auto (requires deep level system integration and privileged Play Services to be present on the device)
Here's an incomplete list of popular Google apps that work perfectly fine on GrapheneOS (in no particular order):
Play Store, Chrome, Gboard, Gmail, Google Drive, Google Photos, Google Calendar, Google Contacts, Google Recorder, etc.
Hope this helps