Paul clearly does not believe Jesus is God.
You need to show exactly how it is that Paul "clearly does not believe Jesus is God." I bolded portions of the verse for a reason:
1Co 8:6 yet for us there is one God, the Father,
from whom are all things and for whom we exist, and one Lord,
Jesus Christ, through whom are all things and through whom we exist.
This is the first thing to notice with this verse: if "from whom are all things" speaks of the eternal nature of the Father, it necessarily follows that "through whom are all things" speaks of the eternal nature of Jesus. It simply cannot be the case that "all things" came "through" Jesus (as the Son), but he is a created being. If the Son did not exist at some point, then the verse is false (same with John 1:1-3, Col 1:16-17, and Heb 1:10-12).
He went out of his way to single of the Father as God.
The second thing to notice with that verse is that, using the same reasoning above, it follows that Paul went out of his way to single out the Son as Lord. Yet, Paul states elsewhere:
1Ti 6:15 which he will display at the proper time—he who is the blessed and only Sovereign, the King of kings and Lord of lords,
That agrees with the OT:
Deu 10:17 For the LORD your God is God of gods and Lord of lords, the great, the mighty, and the awesome God, who is not partial and takes no bribe.
Psa 136:3 Give thanks to the Lord of lords, for his steadfast love endures forever;
And Luke states:
Luk 10:21 In that hour Jesus rejoiced in spirit, and said, I thank thee, O Father,
Lord of heaven and earth, that thou hast hid these things from the wise and prudent, and hast revealed them unto babes: even so, Father; for so it seemed good in thy sight.
So, if Paul is saying in 1 Cor 8:6 that the Father is exclusively God, it necessarily follows that he is saying the Son is exclusively Lord. Yet, other passages clearly attest to the fact that God and the Father are Lord.
As an aside, it is worth noting that the same titles are used of Jesus:
Rev 17:14 They will make war on the Lamb, and the Lamb will conquer them, for he is Lord of lords and King of kings, and those with him are called and chosen and faithful.”
Rev 19:16 On his robe and on his thigh he has a name written, King of kings and Lord of lords.
(All ESV.)
Once again we see the consistent message throughout the NT.
Paul didn't say Jesus is God, but referred to Jesus being in the form (G3444 morphé) when means the shape, form, outward appearance.
I'm just going to defer back to what I've already given on
morphe from Greek scholars.
Furhermore, he did not count equality with God as something to be grasped.
And that means "something to be forcibly retained or held onto." If Paul means that Jesus didn't think he should try and be equal to God, assuming that he is only a man, that really isn't saying anything special at all, since that is the proper view of all humans. Perhaps better put: that was the proper view of all Jews at that time. It would be rather pointless to say, don't you think?
Furthermore, there is only one God mentioned in the context. Paul once again goes out of his way to single the Father out as the only God getting glory.
Phil 2
11and every tongue confess that Jesus Christ is Lord,
to the glory of God the Father.
To say there is only one God mentioned is to fallaciously beg the question and disregard the context of what Paul has already stated, namely, that Jesus was "in the form of God."
Colossians 1:15 says Jesus was created.
This is problematic for you since you deny Jesus existed prior to being born.
Col 1:15 He is the image of the invisible God, the firstborn of all creation. (ESV)
If Paul means that Jesus was created, then he was the first created thing. It could only mean then that he existed long before he was born as a man.
The rest of the context is regarding the church.
Col 1:16 For by him all things were created, in heaven and on earth, visible and invisible, whether thrones or dominions or rulers or authorities—all things were created through him and for him.
Col 1:17 And he is before all things, and in him all things hold together. (ESV)
This is a repeat of John 1:3 and 1 Cor 8:6, and supported by Heb 1:10-12. This is very simple logic:
If "all things were created" through the Son,
then it cannot be that he is a created thing. That is, if the Son was created, then verses 16 and 17 are false, since not everything would have been created through him (he cannot be created through himself; that is nonsense).
But since those verses are true, and agree with other verses, then Paul
cannot be saying in verse 15 that Jesus was created. So is there another way we can legitimately understand the use of "firstborn" and remain faithful to the text? There is.
How then do we understand "firstborn" as it relates to the Son? We look to its other uses in Scripture.
Exo 4:22 Then you shall say to Pharaoh, 'Thus says the LORD, Israel is my firstborn son, (ESV)
Psa 89:20 I have found David, my servant; with my holy oil I have anointed him,
...
Psa 89:27 And I will make him the firstborn, the highest of the kings of the earth. (ESV)
Jer 31:9 With weeping they shall come, and with pleas for mercy I will lead them back, I will make them walk by brooks of water, in a straight path in which they shall not stumble, for I am a father to Israel, and Ephraim is my firstborn. (ESV)
We see then that "firstborn" has meanings which are not literal. We know from reading the Bible that the firstborn had certain rights and privileges but we also see in the verses above that it seemed those whom God loved he called his firstborn, even though they were not in any literal sense his firstborn.
The use of firstborn can mean preeminence without the referent having actually been born. Looking at the significance of
Psalms 89:27, it is a messianic Psalm where God says of David, "I will make him the firstborn." Here, firstborn clearly means that God will put him in a position of preeminence, "the highest of the kings of the earth." David is here the prototype of the coming Messiah, the "firstborn," and has nothing to do with David's being born or coming into being. This is almost certainly what Paul had in mind, and we see something similar in Romans:
Rom 8:29 For those whom he foreknew he also predestined to be conformed to the image of his Son, in order that he might be the firstborn among many brothers. (ESV)
Here it means the same--that Jesus would be the head of all believers. In relation to the Son then, we can understand that
Col. 1:15 is speaking of Jesus's place of preeminence, his sovereignty, and his lordship, over all creation.
A similar idea applies to Rev 3:14. Again, such a verse logically
cannot mean that Jesus was the first created thing, as that would ignore much context of Scripture. What it refers to is that Jesus was the beginner or author of creation, the one through whom the Father created (1 Cor 8:6). That is in full agreement with John 1:1-3 and Col 1:16-17, among others.