The main goal here is to keep my device's IMEI number private, so that it appears to the service provider as if my phone has never used cellular data. By hiding the IMEI, the provider won’t be able to associate the device with me when I use it solely on public Wi-Fi such as in a café, or be able to track me with IMEI if my IMEI number is leaked by some service or app that I accidentally used. They might see that a new device is connected, but they won’t be able to identify that it belongs to me.

Now that I think of it twice I think you got a point Solely connecting to WIFI doesn't seem to leak my IMEI number. But I'm not sure what else will except for using SIMs.

I guess I just don't like the idea that a persistent number could be used to identify me.

Though I'm still curious about:

May I also ask how much information is carried to the second device by using hotspot? By this I meant the phone with IMEI will be able to know my device name, but what else? Will the phone with IMEI also be able to know the device model?

push notifications to work

by push notifications to work you mean?

Sandboxed Google Play is only considered an app in GrapheneOS. It shouldn't have direct access to the IMEI number unless it's explicitly granted permission.

I remember it being explained in the GrapheneOS FAQ that only the OS and the phone (dialer) app have access to the IMEI number. However, I'm not an expert, so I can't say for sure.

Could you please provide a link that confirms whether sandboxed Google Play or any app has direct access to the IMEI number? Thanks a lot!