GS 36 is just reaffirming Aquinas and his doctrine of primary and secondary causality. Primary cause being God is the source of all being and sustains everything, secondary cause being that God created a universe where created things have real, intrinsic causal powers. A fire burns because it has the natural property to, not because God is directly performing an action to burn the wood.
"enjoy their own laws and values" is affirming that the natural world has an objective structure that can be studied on its own terms. Denying that autonomy is occasionalism, which is a heretical view that created things have no real power or nature of their own.
Genisis supports the statement about autonomy. Adam is given the task to subdue the earth, name the animals. To name them means to understand their specific natures. God did not dictate the names, he left that to Adam's human intellect. That's exactly what Gaudium et Spec refers to. Humans utilize their reason to discover the laws of creation and organize human society. We have genuine liberty within the overreaching metaphysical boundries.