By all means, feel free to address, from your own perspective, the questions of what went before Genesis and why God did it? Meanwhile here is my perspective for your consideration.
God lacks nothing, thus His most natural motivation is to give of Himself to others. So God set out to create others apart from Himself. Thus He designed spiritual beings we call angels who were very much like Him in many ways with vast knowledge and abilities. But the only thing which design can create are tools – entities who are and never will be any more than what God made them to be. The result is, in many ways, merely an extension of Himself in much the way a hammer or a car is an extension of those who use them. So God set out on a much more difficult and ambitious task to create something that would not simply be what He made them to be because they would grow, learn, and create themselves according to their own choices.
Now many might wonder at the wisdom of creating something He did not control. Others question the morality of creating things who would suffer in the process of learning or die when they failed. Well I think there is only one answer to both of these questions. God chose to value love and freedom over power and control. In seeking to share with others, it wasn’t enough to simply make beings who would simply be and do whatever he wanted like the angels. The sharing involved is a little superficial when you don’t have to share any of control and responsibility for things, so that you will always only have your own way in everything. Instead God envisioned a more profound idea of love and sharing which requires risk, sacrifice, and a trust which even gives the other person some privacy to live their own life and make their own choices.
But how was an all-powerful all-knowing God supposed to create something that wouldn’t be what He made them to be? It would only work if they had a basis for existence apart from Him and so created a place and time with a system of rules complex enough to support self-organizing phenomenon. And maybe it was with a little tinkering or maybe it even happened elsewhere in an area he hadn’t expected, but some group of self-organizing materials acquired the ability to learn and adapt itself to changes in the environment. Maybe that got his attention or maybe it was only one of billions of such event so when he was tinkering elsewhere, the organisms on this planet developed a means of recording what they learned in the chemical symbolism of RNA and DNA.
Regardless of how much he tinkered with things, some of these creatures eventually developed the neurological machinery for the complex communication of abstract language so that He could speak to them and begin sharing Himself with them directly.