First, nothing about the doctrine of the Trinity teaches that the Father and the Son are the same person. That is the error of Modalism/Oneness. Second, what do you think the purpose of titles is?
Consider these two passages:
Isa 44:6 Thus says the LORD, the King of Israel and his Redeemer, the LORD of hosts: “I am the first and I am the last; besides me there is no god. (ESV)
Isa 48:12 “Listen to me, O Jacob, and Israel, whom I called! I am he; I am the first, and I am the last. (ESV)
Notice also that these are not only statements of monotheism, God says, "I am the first and I am the last." And God says the same thing in Rev 1:8 and 21:6:
Then, in Revelation about God:
Rev 1:8 “I am the Alpha and the Omega,” says the Lord God, “who is and who was and who is to come, the Almighty.” (ESV)
Rev 21:6 And he said to me, “It is done! I am the Alpha and the Omega, the beginning and the end. To the thirsty I will give from the spring of the water of life without payment.
Rev 21:7 The one who conquers will have this heritage, and I will be his God and he will be my son. (ESV)
We then see Jesus say the following of himself in Revelation:
Rev 1:17 When I saw him, I fell at his feet as though dead. But he laid his right hand on me, saying, “Fear not, I am the first and the last,
Rev 1:18 and the living one. I died, and behold I am alive forevermore, and I have the keys of Death and Hades.
Rev 2:8 “And to the angel of the church in Smyrna write: ‘The words of the first and the last, who died and came to life.
Rev 22:12 “Behold, I am coming soon, bringing my recompense with me, to repay each one for what he has done.
Rev 22:13 I am the Alpha and the Omega, the first and the last, the beginning and the end.”
Jesus echoes the words of God, twice claiming titles that God uses of himself. Wouldn't that be blasphemy if Jesus wasn't also truly God? Again, what is the purpose of titles?
Also, about God:
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,
And, again, about 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.
Why do you think Jesus had the title King of kings and Lord of lords written on his robe and on his thigh? Could it be because, as Rev 17:14 states, he actually is the Lord of lords and King of kings, that it truly identifies who he is?
It depends on what you mean. If you mean the man Jesus, then no, of course not. If you mean the Son, then it is absolutely crystal clear that he preexisted. I've given you many verses, including those from Jesus's own mouth, but I don't think you ever addressed them:
Joh 1:1 In the beginning was the Word, and the Word was with God, and the Word was God.
Joh 1:2 He was in the beginning with God.
Joh 1:3 All things were made through him, and without him was not any thing made that was made.
Joh 3:13 No one has ascended into heaven except he who descended from heaven, the Son of Man.
…
Joh 3:16 “For God so loved the world, that he gave his only Son, that whoever believes in him should not perish but have eternal life.
Joh 3:17 For God did not send his Son into the world to condemn the world, but in order that the world might be saved through him.
Joh 6:38 For I have come down from heaven, not to do my own will but the will of him who sent me.
…
Joh 6:62 Then what if you were to see the Son of Man ascending to where he was before?
Joh 8:23 He said to them, “You are from below; I am from above. You are of this world; I am not of this world.
Joh 8:24 I told you that you would die in your sins, for unless you believe that I am he you will die in your sins.”
Joh 12:44 And Jesus cried out and said, “Whoever believes in me, believes not in me but in him who sent me.
Joh 12:45 And whoever sees me sees him who sent me.
Joh 12:46 I have come into the world as light, so that whoever believes in me may not remain in darkness.
Joh 12:47 If anyone hears my words and does not keep them, I do not judge him; for I did not come to judge the world but to save the world.
Joh 12:48 The one who rejects me and does not receive my words has a judge; the word that I have spoken will judge him on the last day.
Joh 12:49 For I have not spoken on my own authority, but the Father who sent me has himself given me a commandment—what to say and what to speak.
Joh 13:3 Jesus, knowing that the Father had given all things into his hands, and that he had come from God and was going back to God,
Joh 16:26 In that day you will ask in my name, and I do not say to you that I will ask the Father on your behalf;
Joh 16:27 for the Father himself loves you, because you have loved me and have believed that I came from God.
Joh 16:28 I came from the Father and have come into the world, and now I am leaving the world and going to the Father.”
Joh 16:29 His disciples said, “Ah, now you are speaking plainly and not using figurative speech!
Joh 16:30 Now we know that you know all things and do not need anyone to question you; this is why we believe that you came from God.”
Joh 16:31 Jesus answered them, “Do you now believe?
Joh 17:3 And this is eternal life, that they know you, the only true God, and Jesus Christ whom you have sent.
Joh 17:4 I glorified you on earth, having accomplished the work that you gave me to do.
Joh 17:5 And now, Father, glorify me in your own presence with the glory that I had with you before the world existed.
Joh 17:6 “I have manifested your name to the people whom you gave me out of the world. Yours they were, and you gave them to me, and they have kept your word.
Joh 17:7 Now they know that everything that you have given me is from you.
Joh 17:8 For I have given them the words that you gave me, and they have received them and have come to know in truth that I came from you; and they have believed that you sent me.
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.
Gal 4:4 But when the fullness of time had come, God sent forth his Son, born of woman, born under the law,
(Note the similarity with Isa 9:6: For to us a child is born, to us a son is given; and the government shall be upon his shoulder, and his name shall be called Wonderful Counselor, Mighty God, Everlasting Father, Prince of Peace.)
Php 2:5 Have this mind among yourselves, which is yours in Christ Jesus,
Php 2:6 who, though he was in the form of God, did not count equality with God a thing to be grasped,
Php 2:7 but emptied himself, by taking the form of a servant, being born in the likeness of men.
Php 2:8 And being found in human form, he humbled himself by becoming obedient to the point of death, even death on a cross.
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.
Heb 1:8 But of the Son he says...
...
Heb 1:10 And, “You, Lord, laid the foundation of the earth in the beginning, and the heavens are the work of your hands;
Heb 1:11 they will perish, but you remain; they will all wear out like a garment,
Heb 1:12 like a robe you will roll them up, like a garment they will be changed. But you are the same, and your years will have no end.”
(All ESV.)
The Bible is unequivocal in its message that the Son existed before the incarnation.
