If not, what can be known about God?
What is known about God?
Or if knowledge about God is limited, has this limitation been defined.
Any God that you believe is real. WRT knowing your God, what are the possibilities?
What is not possible?
One way to answer this question is use a science fiction scenario that would appeal to the atheists, to gain some perspective. Picture aliens from a distant part of our Galaxy coming to earth. These aliens are a million years ahead of us in terms of technology and tech enhanced bio-evolution. They are nothing like we could ever imagine, being so advanced.
Seeing we are so far behind them, how much can we know and understand them, as they are? They would understand our limitations and and may decide to dumb down; assume a new form and nature, so they can communicate with us and not spook this fragile and infant species. This less evolved species; earthlings does not call the shots, even if they are arrogant.
This level of dumb down for the aliens may not be easy, in terms of wide scale perception, so they may also need to select certain members of our species, via neural brain scans, as having the potential neural matrix to intercept messages; prophets. Since seeing is believing, and since we cannot see them as they are, they will still be denied as they are. However, we may believe based on what we see and think they are; the dumb down version that is conscious.
If God created the universe, he would be billions of years ahead of these aliens who are a million years ahead of us. God would have to dumb down to the nth degree, to even to reach those sophisticated aliens and not spook them.
For the earthlings, the amount of needed dumb down would be amplified, so God may need to use some semi-advance intermediaries, who can catch a more advanced dumb down drift, They can then dumb down enough to reach the bottom feeder, earthlings. There were many prophets such as Muhammad. Jesus was the son of God and came as an intermediary.
Since there is so much separation from God the creator and the bottom of creation; humans, there will be misunderstanding, as people attempt to carve the nature of a dumb down version of God into stone and limit God to that. Faith in things not seem is important since it leaves open the option of change as we advance and can gain new perspective that can advance us to a place of less dumb down.
The true nature of God is not known to us. What we know is only what we have been allowed to see. The prophets see more and the intermediaries see even more than that. However, the latter two still need to dumb down what they know, since they are still dealing with those who lack a more direct connection to the deeper knowledge, that will come with time.