A question like this cannot be answered in 25 words or less in a forum such as this.
A couple of observations: The term "religion" is vague and embraces a multitude of beliefs. The Christian faith is predicated on certain principles 1) man is not the measure of all things, also intellectually. 2) There is a God who has spoken in a form which man can know with certainty and understand 3) That knowledge embodied in his revealed word can be studied and known systematically. Theology is a science.
The short Biblical answer to your question is God's revealed name is "I AM" Exodus 3:14. It is a declaration of His eternal self existence, the doctrinal term is His "aseitas." Moreover He declares I AM THAT I AM, that is, He is eternally unchangeable in His self existence. Therefore in the context of His word to Moses in Exodus, He has not changed respecting His promise, though 400 years have passed. As God says I AM, so we say HE IS, that name is the name rendered LORD in the Old Testament or Yaweh in Hebrew or Jehovah in English. It is also the Root of Jesus' name Je-sus literally Jehovah-salvation.
Christian theologians have dealt with the kinds of questions you are asking at length. Get a copy of John Calvin's "Institutes of the Christian Religion." After an introduction to the king of France, Calvin addresses exactly the questions you raise in the opening chapters of the Institutes. The books and similar works have been available for centuries.
They are not light reading
Quite the understatement. Regardless of language you tackle them in.
My grandfather, a preacher who thought I was ignorant because I couldn't read greek, would toss a tome like that to me when I asked questions.
It's a hard slog. But well worthwhile.
/johnny