Bad news - Google doesn't need an account to track your app downloadsm
Perhaps you'd be more interested in creating a website that downloads all the apps from the play store using burner accounts and makes them easily anonymously accessible.
GrapheneOS is not sending app downloads to Google that happen outside of Google's apps, which I don't use. And there are other ways to download APKs from the Play Store; EFF even makes their own tool for it, and there are third-party archive sites and alternative non-Google app stores as well.
Perhaps you'd be more interested in creating a website that downloads all the apps from the play store using burner accounts and makes them easily anonymously accessible.