Why did God create the Universe?
It doesn’t say in the bible (or – correct me if I’m wrong – in any other holy text from any other tradition either)
Perhaps we can only speculate?
I think he did because he wanted to bring meaning to his own existence
Perhaps he felt bored and lonely?
Also, is humankind at the centre of creation or did it just arise by chance?
I believe the purpose of the universe is so that there can be a humankind, a body of beings God can have a relationship with, therefore I believe humankind to be at the centre of creation (and made in God's own image)
Those are my thoughts on the matter
We know exactly why God created the universe. Because we are told that humans are made in God's image, this naturally follows that God has human emotions. Now, God is probably centuries and eons and so on, better able to deal with things than us and less prone to actual killing (but people still die because their bodies aren't made to last forever, humans literally means dirt people like humus not be confused with hummus).
Before the creation of everything else, we know that the universe is an empty place and there is shapeless void swirling about. I can think about isolation better than most, as the majority of my jobs have been just me working for someone. It starts to get to you. So I can imagine pretty quickly how quickly I'd start creating stuff after being in a large space with nothing to watch but swirling void. One day at most, maybe even an hour.
Bored and lonely? Yes.
We know from Taoist Yin Yang theory, and from our understanding of Judaism that God is effectively Light and this shapeless void is also God. Essentially, Undifferentiated split into God the One and God's void, so all of that is kinda the Dark part of God, the same as all of us have shadows.
We also know that God kinda used Light to give order and form to this shapeless void, splitting it into things. Night and day, sun and moon, Earth has land and sky as well as land and sea, different animals, and finally male and female. Yet we know that God isn't really a He from this. We can safely say that either God has no fixed form, or that God is or was kinda a double sided entity (bottom line on why human look like they do, they are two halves).
We also glean an important bit from all this, that because humans are split, we have God the One (God) and God the many (all of us collectively). We have stupid feminists who haven't figured it out yet, the reason God is a He in most Biblical text is because we are intended to be She, we're supposed to be in a happy marriage.