That’s not necessary. It’s really simple:
God wants everyone to believe and spend eternity in heaven but some people will never be able to believe. Therefore, he screwed up.
Necessity is a logical concept. You assume the existence of binding, universal, invariant, objective laws of logic without a coherent foundation for the existence of such laws in a materialistic universe of chance/necessity. If it's really simple you shouldn't have any trouble accounting for your assumptions.
God wants everyone to believe and spend eternity in heaven but some people will never be able to believe. Therefore, he screwed up.
Again, you assume some sort of standard that God purportedly violates. I should like to know the nature of this standard to which you refer and what its foundation is.