Imagine you create a video game that is a simulation of an imaginary world. Hypothetically, in this game world there are self-aware non-player characters (NPCs).
This world would be a closed system, meaning that like our universe, once it is created nothing new can come into the world that isn't already in the world. For example in our world you cannot create new energy or new matter. You can only use that which already is, and combine these things to make "new" things, but their possibility already exists within the closed system.
By exploring the game world, these NPCs could only ever come to the logical conclusion that time and their virtual world has always existed. And from their perspective it would rationally be true, because thinking of a time before time would not be logical. Time cannot exist without space, energy, matter and the laws of physics. So their world has by definition always existed, and never not existed, because nonexistence doesn't exist.
The only way the NPCs could even imagine the concept of a world outside of their world or a creator, is if the game creator intervened somehow and implanted these ideas or concepts in their world.
But even if the NPCs had been given this idea that something outside of their world might exist, they could never actually get any evidence of this outside world themselves. Because it is outside of their frame of reality which is a closed system.
Therefore the evidence that God exists is that we can imagine a higher power and the concept of a God that is outside of our reality.
I'm not saying that every god we can imagine exists, because people can mix the idea of a higher being with things that already exist in the world and create their own counterfeit version of God. Such as pagan religions which worship gods that look like animals or the sun, or the moon, or whatever.
In the Bible however, the true living God says he is not of this world, he was never born and will never die.