Congratulations on your first steps in GrapheneOS!
In order to best help you and give relevant suggestions, we need more information of who you are trying to be private from.
If your threat model is particularly sophisticated, it may be recommended that you do not use a sim card, or at least never when your phone is at home. Instead, exclusively rely on WiFi. It may also involve desoldering your microphone and camera and only make calls using an earpiece.
These are not recommendations, but simply examples of how far one can go with respect to their threat model. If you would rather want to avoid "regular" spying by google, Facebook and the likes, you may be better off selecting a private DNS (for example Mullvad's extended DNS which comes with social media filtering https://mullvad.net/en/help/dns-over-https-and-dns-over-tls ). You would need to make sure you do not install Google services (nor microg) and especially no google apps.
Much more can be said, but we would need specific information about your case to provide better guidance.
EDIT: I do not want to give the impression that GrapheneOS does not make a good job in improving your situation already. They do! But to do more you would need to justify it with your threat model, that's what I'm getting at.