GrapheneOS only support Pixel devices.
Can you run common apps from the play store if you choose?
https://discuss.grapheneos.org/d/10855-google-play-store-install
I think you can install Google Services (including Play Store) if you want, but there are alternative like Aurora Store that lets you download apps from Play Store without Google Services, but obviously you can't buy apps from it
the main concern is probably banking apps or some apps that require Google Play Services to run