233328 Thank you, I didn't know those particular services.
I did already try my alternative SIM and some fake ones, but Google actually checks if the number is used only once. So this is not going to be that simple given the popularity of Google.
I did try Aurora Store, it's fixed, currently it looks like the simplest solution to me.
Either way I'm fine, I'll manage. But what is actually the most interesting to me, what's GrapheneOS team official stance going to be? Get a fake phone number?