Well, you don’t have to worry about the so-called devil where I’m concerned.
There ain’t no such critter, and the concept undermines monotheism.
The existence of angels, good and bad, does not undermine monotheism any more than the existence of onedoug undermines monotheism. Angels, good and bad, are creatures, not “gods.”
I take it you think God is misleading -— or misled —— concerning the devil?