GrapheneOS actually recommends against using Aurora and instead just using the Play Store, so this shouldn't really hurt users. For extra privacy, you can sign into the Play Store with a Google Account that isn't tied to anything else.
> a Google Account that isn't tied to anything else. Isn't that pretty much impossible? You need a phone number for verification, which effectively ties it to that phone number.
You can also just get a burner phone number for a few bucks.