Guide on how to create an android qube. I would recommend running either bliss os or android x86 and not anbox as it has sandboxing and other security features disabled, according to this comment. As far as I can tell, there is no graphene os templateVM available for qubes at the moment, nor are there any minimal android templates similar to these.
If you are concerned about SS7 vulnerabilities, I’d recommend using an online SMS PVA service. Here are a couple examples that accept monero and have onion addresses for enhanced privacy & security: