As a lifelong Trinitarian (baptised by the Church of Scotland in infancy, baptised into the Scottish Baptist Assembly in youth and received into independent fellowship in adulthood) I would say that this question is fundamental to the progressive revelation of Deity from the beginning of time.
I am brief for I am certain that others will express other aspects of this question and I need not strive, on my own, to do everything. For we are not solitary : we, Trinitarians, abide in plurality.
John’s words (the Word was with the Deity … and God was the Word, John 1:1, literal) are not uttered in a vacuum, but are part of a progressive revelation that begins with the word Elohim, Genesis 1:1, with the utterance of Deity ‘Let us make’, Genesis 1:26, and with the commandment ‘let light be’, Genesis 1:3, literal).
The use of the collective noun ‘elohim’ and the very fact that Deity speaks of ‘us’ - ‘let us make’ and ‘the man was as one of us’, Genesis 3:22 (see YLT for the correct Hebrew perfect tense) - that very fact poses the most basic of questions to anyone who seeks to know the ‘the true God and eternal life’.
That 'the Lord came to Abraham' and 'three men stood' and Abraham said 'My Lord' poses exactly the same questions, Genesis 18:1,2.
That when Moses sees a burning bush, he is viewed by Jehovah, and Elohim dwells in the bush and the Angel of the Lord makes utterance from the midst of that bush, enforces those same questions, Genesis 3:2 and 4.
That David evidently knows one whom he refers to as ‘the Lord’ and one whom he refers to as ‘my Lord’, Psalm 110:1, and that he desires not that ‘the Holy Spirit’ should be taken from him, Psalm 51:11, poses the questions all over again.
And that there should be a spectacle of three persons in a searing heat, a fiery blaze - a depiction of everlasting burnings - and that there should, also, be another figure, one of that group, yet, at the same time, an addition to that group, referred to as ‘son of Deity’ by the highest possible authority on earth at the time, Daniel 3:25, ensures that those questions lose neither their potency nor their intensity with the duration of the centuries . . . .
. . . . until John the chosen apostle utters the concept yet again and states that, at the instant of ‘beginning’ there is One who is both ‘with God’ and who is also ‘God’.
‘Theos’ (which can be very adequately translated as ‘Deity’ in the English language) denotes a matter of nature. It is the state of nature which is other than human and other than angelic. Yet it can, also, refer to that which is like itself. ‘Said I not ye are gods’, Psalm 82:6 and John 10:34, expresses that if men are godly, then can they be viewed as gods, but only if they ‘partake of the divine nature’.
‘The sons of God’, Genesis 6:4 and Job 1:6, are they who, made in spirit fashion, and viewed as such (until they relinquish that form and irreverently and erroneously leave their proper estate and take another form) are viewed as ‘gods’ in their creative nature : but only as long as they abide in it.
But he who - from the beginning, in an uncreated existence - was such, is revealed to be not alone.
That divine nature is revealed to be something that is shared.
And if shared, then only possibly shared (in the very nature of what that divine essence is) in a perfection of love, in a perfection of unity and in a perfection of unanimity : a unanimity of purpose, of will, of desire, of intent, and of determination.
For the Deity desired not to dwell in isolation.
Deity desired to bring many sons to glory, Hebrews 2:10.
And this - the Fatherhood, the Sonship and the Spirituality - of a union of divine love and purpose and perfection, is that that which inspires the worship of those who enter into that unity, through a new begetting (a birth from above, a birth anew, a birth again, a birth of water and of Spirit, and a birth of God) and through salvation. God dwells not alone : nor is it ‘meet’ for ‘the man to be alone’.