Is this an illegal combo??

I’m playing RDA right now I just recently put in 3 copies Pot of Prosperity, I figured it would be a nice addition to Bystial Dis Pater or Red Zone to revive the exacavated extra deck monsters that were banished plus you get an card of your choosing. I feel like it’s an illegal combo cause how simple it would be to bring out your lvl 12 boss monsters like Red Supernova Dragon or a Cosmic Blazar

Its this legal?