Authy likely doesn't actually want to ban GrapheneOS. However, that's what the Play Integrity API does.
We believe they adopted Play Integrity to make it appear that they're improving security after the breach including by making hard decisions which make people upset. However, using the Play Integrity API does not in any way improve the security of their app.
They COULD follow our guide and permit GrapheneOS but likely won't. They don't understand what it is or how many users it has.