If the planet is dead, we as a civilization get the privilege to do whatever we want with it. Also a dead planet means the idea of the Monotheistic God kind of remains.
Ignorance is bliss.
I don't follow why life on another planet would have any bearing on the idea of a Monotheistic God.
The garden of eden could be in some far flung galaxy, from which we “life”, were expelled as microbes, thanks to the sins of relatives we wouldn’t recognize. The rib of Adam could symbolize the arbitrary evolution of sexual reproduction from asexual origins. The forbidden fruit could represent some inevitable nuclear holocaust spurred on by some intra-species conflict, which prompted life to be cast out and begin on another planet. Something unique about our shape of life means that we’re stuck in a cycle of destructive evolution that cannot be saved from itself, excepting for the divine intervention of some less imperfect shape of life.
Anyways, I’m rambling! I hope this sparks somebody’s theological-scifi bug and produces a mildly entertaining narrative in somebody else’s head. :)
Stuff like that.