"I'm not a Christian so please stop harping on what your...

"I'm not a Christian so please stop harping on what your Christian mates do with me."

You ARE quoting them and the said scholars, by adopting their FALSE translation that "He" was with God in the beginning.
The ONLY definition where you have "he" from the Greek word is -> "This" and this is not a person or being, with the God, it is a logos/plan to, toward, with the God and part of that is CLEARLY shown to have been expressed forth from God, by John 1:3.

"Salvation through Christ was in the plans of God in the beginning, but.." = in the mind and plans of God, as numerous scriptures show and Jesus references them.

"Through him all things were made; "

Isa 44:24 - Thus saith Yehowah, thy redeemer, and he that formed thee from the womb, I Yehowah that maketh all things; that stretcheth forth the heavens alone; that spreadeth abroad the earth by myself;
Psa 33:6, 9 - By the word of Yehowah were the heavens made; and all the host of them by the breath of his mouth.
For He spoke, and it was done; He commanded, and it stood fast.

What does Jesus say about the making of man;
Matt 19:4 - And he answered and said unto them, Have ye not read, that he which made them at the beginning made them male and female,

"He" is certainly Not 'we' three made man.
Jesus implies that he found out by reading the scriptures, like many other things, which he quotes.
Are you going to try and tell me, that Jesus wouldn't of mentioned that he was there when God made man ???
----------
"In him was life, and that life was the light of men."

The Him here is Yehowah, the God and Father who IS The Word.
In him life was (as expressed forth in Gens creation John 1:3) = his inner logos here, words of Spirit and life (words) to which he gave and raised the son in Deu 18:18, to have life in himself John 17:8, 6:63, 68.
And that life = words when expressed forth, is the light of men Psa 119:105, that is the True Light that enlightens every man coming into the world, including Adam - John 1:9.
God is light 1 John 1:5, Father of lights James 1:17, His word is light Psa 119:105.

After Jesus's raising in the word, he had it without measure, resulting in;
John 12:46 - I am come a light into the world, that whosoever believeth on me should not abide in darkness.

Expressing the God and Fathers words out, also made him the express image of God's Person - Word, The Word. Heb 1:3, KJV, John 14:10.
(your words being your spirit person expressed).

We are to fill up with the word and;
Matt 5:14 - You are the light of the world. A city that is set on a hill cannot be hidden.
------------
"Otherwise in your post, there you go quoting scripture that supports the Trinity, and you don't appear to realise it."

I'll be happy for you to show me, how my post do anything of a sort, I would suggest that is your misunderstanding, but until you quote such, I don't know what parts of my post you are referring to, and of which you think do such.
--------------
"By claiming that Jesus only first existed at his incarnation ignores this scripture."

As provided, it appears that you are the one ignoring True scriptures.
Not to mention, by quoting the name Jesus, that only come about after this, No such thing -> incarnation.

There are many OT prophesies of the Jesus to be and not a single one of them even hints at, that this future one to be, already existed in one form or another, that would come down and take on flesh or enter Mary, other than a plan to be, in the mind of God.
You cannot tell me, that if this future one already existed, that that wouldn't be mentioned in the OT.
That would be deemed as, lies by omission to not include it, if he already existed.

The OT is full of, God trying to make himself known and his word accepted and followed.
With this in mind, you cannot honestly tell me, that if God consisted of 3 persons, that this would not have been made known, LOUD and CLEAR.
Other wise, if they were worshiping a singular being as the Jews do (rightfully so), that would be deemed as following another God, if he was 3 persons.

A bit of logic and common sense needs to come into the picture and also, WITH the overall theme of the Bible, which dictates translations.