xyzalphabeta aha so then the questiom becomes, who do you allow to know that the device is linked to your identity.
Yes, with a SIM card it's your cellular ISP. Without a SIM card, but with Airplane mode off it's cellular base station operator and it can be correlated with the store who sold the phone via IMEI (store cameras are the next step). Without a SIM card, but with Airplane mode on it's your current WiFi access point owner.
Choose your poison :)
xyzalphabeta Basically needing a physical sim is an imperfect setup and thus inherently comes with privacy flaws.
And eSIM also.
xyzalphabeta I guess this was why i thought of the call forwarding setup because this allows for cellular within linking the device.
Right, but moving your existing phone number from a SIM to a VoIP provider is even better. Your current mobile ISP (which should be doing call forwarding in your scenario) won't have your call logs, text messages, and metadata. Also, you can just drop current contract with them and stop paying for cellular since you don't need their services anymore.