I would count as tangible something that is measurable and repeatable under controlled conditions. I cannot understand why a benevolent god would be so cruel as to deny that, while requiring our belief, as a prerequisite to salvation.
Personally, I subscribe to process theology. At the heart of process thought is the belief that God is love; not merely loving, but love itself. Love entails freedom — freedom of thought, freedom of choice, freedom of action; God cannot — not “will not”, but “CANnot” — do anything that would limit or deny us that freedom. God can lure us towards a relationship with Them, lure us to follow Their will, but cannot coerce us. IMO, for God to provide us with measurable, repeatable evidence for Their existence would be a form of coercion; with such evidence, we would have no choice but to believe.
Also, because I believe God is love, our belief in Them isn’t required; the only prerequisite to salvation is good thoughts, good words, and good deeds. It’s not a doctrine found in mainstream Christianity, but I’m not a mainstream Christian.