There is little privacy to WhatsApp messaging service. Your conversations are encrypted, but the rest of the metadata is available to Facebook, authorities, data brokers, etc. Pen & trance order for WhatsApp reveals your contacts list, who you contact, when, phone battery level, and enough of other metadata to profile and geofence you. WhatsApp pen & trace order provides live data on you. GrapheneOS and/or VPN help in prevening leaks of information that aren't supposed to be there by design/regulation/standard, but they can't do much about services that are allowed to provide whichever data about you based on their privacy policies.
Use Signal.