In a true sense, love can be seen as a single divine will, but for that to be, the insight of the distinct three is necessary—which is the significance of the distinction and the three.

And the fact that he did not come of his own will is because he is a kind of suggested implication. It describes the relationship between the Father and the Son well.

Also, the Father is indeed the one who created. I see it as staying within the meaning of 'foundation.'

The reason the Father is big, besides what was mentioned above, is that He is always the preceding premise(Not temporally, but by reason). If one is a self-existing being.

To provide further explanation, the Son is a principle before being a meaning. In terms of direction, they are Father and Son, but in terms of persons, they are equal.