Ok, just for kicks, let's push into the annoying challenges of the Trinity and Incarnation...
If we just look at John 1:1, we get an idea of how daunting this will be (as the discussion to this point has shown). There, we have an entity John calls "the Word" and an entity John calls "God." John says the Word was both "with" God and "was" God. For one entity to be both "with" a second entity and to actually "be" that second entity is outside of our natural daily experience, and is not something either our minds or our language are fully equipped to handle.
Verse 3 makes clear that the Word created everything, and that the Word itself was not created.
Verse 4 shows the Word as the source of life and "light."
The next few verses talk about "the light," and the fact that John the Baptizer testified about Him.
We see that the Word "became" flesh and came to live among us, and that He came "from" the Father (v. 14).
Verse 18, reportedly notoriously difficult to translate, reaffirms that the Father and the Word are both God:
"18 No one has ever seen God. The only one, himself God, who is in closest fellowship with the Father, has made God known." (NET)
By v. 29, it is clear that "the Word" is Jesus. He has so far been called "God," and has been shown to be distinct from "the Father." In the next few verses, He is referred to as the "Lamb of God" and the "Chosen One of God," each expression suggesting He is distinct from God, even though the early part of the chapter referred to Him *as* "God."
"In the beginning" in John 1:1 is a rather clear allusion to Gen. 1:1, esp. in the Septuagint, which was the (Greek) translation most widely used, at least in the Roman Empire.
In the Hebrew, Gen. 1 exclusively refers to "God" (Elohim, Strong's number 430). Gen. 2 and 3 (beginning with 2:4) almost exclusively uses the compound name "LORD God" (YHVH Elohim, Strong's numbers 3068 and 430), and then Gen. 4 switches to mostly using just "LORD." After that, no term is used with great consistency. This is enough to establish that the Creator is known as "God" (Elohim in Hebrew, Theos in Greek), "LORD" (YHVH in Hebrew), or a combination of those.
In Ex. 3, we have the famous account of the "burning bush." There, God repeatedly refers to Himself as Elohim. But when Moses asks who he should say sent him, God reveals the Holy Memorial Name "I AM," which is the root of every occurrence of "LORD" (in all caps).
Deut. 6:4, the "Shema," declares that Elohim, the I AM, is "one."
Ex. 20:3, the First Commandment, explicitly declares there is to be no other god besides I AM. This is reaffirmed many places, including Deut. 4:35, 39; Isa. 43:12; 45:14; Joel 2:27.
So God is I AM and I AM is God, and there is no other God.
Some may wish to claim that Jesus stopped being God at some point. Offhand, I cannot directly and completely refute that, meaning I don't know of a place where He was directly called "God" during His earthly ministry. I have shown that He was called "God" before the Incarnation. He was called "God" in John 20:28. (In that same approximate context, He had implicitly claimed divinity in 20:22, which clearly calls to mind Gen. 2:7.) But this is post-Resurrection. I *can* cite John 8, wherein Jesus emphatically identifies Himself as "I AM"; this was the most important revealed name of God in the OT. But I don't know of Him being called "God." So to claim that Jesus at some point ceased being "God" would mean I AM was still I AM, but was not God until He became God "again" at the Resurrection -- a bizarre notion, but... whatever. In any case in Revelation 1:17; 2:8; and 22:13, Jesus is identified with terms reserved for Elohim / YHVH in Isa. 44:6; 48:12.
Scripture is clear enough in teaching that Jesus was, is, and always has been "I AM." It is clear that He was and is God. It is clear that He was also in some sense "with" God. It is clear that the Father is also God. And it is clear that there is only one God.
It is rather less clear on how to neatly harmonize all of that.