Right. Outside conservative Protestantism — which isn’t what you’re looking at — creation doesn’t mean 7 days and a young earth. You can certainly understand the specific Genesis stories (remember, there are two different ones, Gen 1 and 2) as legendary. But the idea it reflects underlies the whole Bible, which is that God is responsible for the universe.
That means he’s legitimately in charge. It also means that the universe reflects his nature. One of the big mysteries for scientists is why the mathematical models work so well. Why is the universe constructed so rationally? After quantum mechanics we no longer thing it’s quite so much like a simple machine, but still, why can it be described so well by laws? The Christian answer is that its rationality reflects God’s rationality.
Not only does the universe reflect God, but we do. We are made in his image. If you try to look at the Bible as a whole and ask what the overall plot is, it is God trying to restore (or if you consider the Fall to be legend, to establish) his image to man. And through man, to the whole universe. He established a covenant with Israel to help it develop that way. When that failed, he sent prophets. Finally, he sent his son.
Christians can be (and probably should be) strong and forthright. But if God is our creator, and our purpose is to reflect his image, then we should be trying to develop in a way that does that. Jesus’ normal term is obedience, not submission. There’s overlap, but they may not be identical. But if God is really our creator, and the universe and our own lives reflect him, then what he asks of us should be good for us. So it’s like a young child obeying parents. Parents who are competent and want their children to grow into strong, independent people.
One of the strengths or weaknesses (depending at least in part upon our relationship with our own parents) of Jesus’ continual reference to God as Father is that what it means depends upon our image of what it means to be a father. Is it a father who just wants his children to do what he says? Or is it a father who is concerned about developing his children into the best possible people? The meaning of obedience and submission depend upon that concept.
There’s one other core concept that should be mentioned. That is that people are part of a web of relationships: God and man, husband and wife, parent and child, citizen and government. Some theologians have defined personhood as being constituted entirely be the relationship of the person to others.