Comment by strcat

They don't need to do anything to support GrapheneOS. They only need to stop actively going out of the way to block it and any other alternative OS via the Play Integrity API. They put significant effort into blocking anything other than iOS or a Google Mobile Services Android stock OS certified by Google. They're not only blocking a non-stock AOSP-based operating system but rather anything other than iOS or a Google Mobile Services Android device certified by Google.