Nice, you can stack sats with the difference. However, I'd be extremely careful about using that device now since Google can correlate its IMEI with your purchase and probably that feeds info straight to the NSA. If you used your name, address, credit card, and/or transfer your number to it, corporate and government surveillance efforts will have no problem tracking a lot about you. Graphene will help with a lot of general security and apps but purchasing a device with cash and some form of disguise against the store's facial recognition (or straw purchaser) is probably the easiest way to achieve a more meaningful privacy overhaul. Along with running the phone's data through an e-sim like silent.link (with KYC free sats) and a VPN, then porting your number to a VOIP stack like jmp.chat or mysudo, you can really improve privacy. Michael Bazzell's work on this is very helpful if you want to check out inteltechniques.com. But I don't want to scare you because every incremental improvement is a win down the rabbit hole of privacy.