Before asking if God exists one must define God.
And even so, the bottom line is that "God" exists in the minds of those who believe "God" exists. There is no data, no evidence, no hint that "God" exists anywhere else. The Christian and Muslim "God" is a tautology, defined upon itself.
No matter how many people believe in the same fantasy, without data or evidence it is still a fantasy.
And just because there are unanswered questions does not mean there is a "God".