You say “If science made God irrelevant…” That’s a very big ‘if’. If science has chosen not to see God, then that version of ‘science’ is arguably willfully blind. Many great scientists have been and still are spiritual or religious, and find atheism somewhat ridiculous.

“the consequence of the age of enlightenment was the terminal diminishment of God”. So much the worse for the age of enlightenment then, to be so deluded. That age is nearly over and is in terminal decline, more and more scientists realising its inadequacy.

The reason for God (and there are many different visions of what that word means) beyond spiritual comfort is that it brings us closer to the truth. The Enlightenment, despite its good points, was ultimately hubristic, overconfident, too sure of its own rightness.

You speak of Nietzsche as if he were some kind of guru, prophet. This is highly debatable. Of course, that is probably how he saw himself. Somewhat like the ‘Enlightenment’ then.