If as a materialist you think an idea is irrelevant because you cannot touch it, I think you’ve missed the point entirely, because what matters is that ideas touch you. If you think similarly, maybe like most Theists do, then what probably matters to you about God is the reality of God and since God cannot be touched, then I suspect like many Theists, great and heated debate is focused there. Instead, there is the very inarguable sense that matters to believer and non and that is that the idea of God touches us all.
The most legitimate Theology will then only concern itself with the images of this ineffable “Big Other” we are forced to create. That’s because the most fundamental question when it comes to the idea of God is how we are going to react to that idea, what is one to do because of the idea, whether it is believed true or not.
From there, Theist and Atheist can and should, together, challenge these images because if they are not unfettered images of humanity at its best, then we have no use for them at all, nor should we.
Ultimately, the idea of God is the very idea of our ability to be God, as we imagine God to be; as any other conception is incomprehensible and therefore, literal nonsense.
Just a thought.