One of the great things, among many others, of GrapheneOS is that you can choose how much integration you want with Google or any other corporation.
It has so many options, that it can be overwhelming. I'd start without using profiles, installing sandboxed Google Play Services, Android Auto... All the apps en the GrapheneOS Apps app. I'd even enable everything and give all permissions to those apps. Install all the Google apps that come with a pixel, like the Pixel camera, Google Photos, GBoard... At that point, you'd have a similar experience to that of stock Pixel, and a similar "exposure to Google" except that all these apps are sandboxed, so better than stock Pixel, and you benefit from all the added security GrapheneOS has built in.
Then, as you use the phone, you can gradually find more private alternatives to Google apps, uninstall whatever you don't use, revoke whatever permissions are not needed, you can explore using profiles, alternative stores, tweak settings to increase your security and privacy etc.
So I'd suggest starting with a setup as close as possible to the experience from a stock phone, and gradually explore all the possibilities that GrapheneOS allows you to have, but with baby steps, you don't want to get overwhelmed or burned out.