The question stems from John 1:18 “No man hath seen God at any time; the only begotten Son, which is in the bosom of the Father, he hath declared him.”

The method of reasoning is understandable: since no one has seen God and Jesus was seen by many, therefore Jesus is “not God”.

This confusion results from failure to understand who the God referred to in John 1:18.

In general, when the NT speaks of God, it refers to the Father God. But when Jesus is referred to, the words “I AM”, “Logos” and “Lord ” are used. In the OT, Jesus is referred to as YHVH ELOHIM, I AM, EL SHADDAI.

That Jesus is God Creator is clear in John 1, the Logos Creator. And in John 1:14 ” And the Word/Logos was made flesh, and dwelt among us, (and we beheld his glory, the glory as of the only begotten of the Father, full of grace and truth.”

As to the differentiation between the God the Father and God the Son (“Lord”),
Eph 1:3 “Blessed be the God (Theos) and Father of our Lord (kyrios)”Jesus Christ,”

Likewise, Peter differentiated the two, as in “Blessed be the God(Theos) and Father of our Lord (kyrios) Jesus Christ,”(I Pet. 1:3)

In essence, indeed,  “no one has seen God (the Father Theos) , but has seen Jesus, the God kyrios, the Lamb Meschiach (the “Son of God”, “Lord God”, “Logos”, “YHVH ELOHIM, “EL SHADDAI”).

See also:
https://ebible.com/questions/3196-why-is-god-so-different-in-the-old-testament-than-he-is-in-the-new-testament
https://ebible.com/questions/3988-what-did-jesus-mean-when-he-said-i-am
http://yahushua.net/YAHUWAH/chapter_08.htm
http://www.exodus-314.com/part-ii/the-meaning-of-ligehyeh-asher-ehyehlig.html