I have a question - is The Strange a setting with subjective, belief based reality as per Mage: The Ascension, Unknown Armies and some other settings? I don't own it and I only have a passing familiarity.
Sort of but not like Mage. There are three kinds of reality in the Strange.
First, there is the material universe. Prime worlds like Earth exist here. The physics in this universe are just like ours.
Second, there is the dark energy network or chaosphere. This underlies normal reality. It was created long ago as a means of intergalactic travel. The original creators made it so that they could mentally enter into it, travel long distances inside it and they print themselves new bodies at some distant point in space. Long ago, the system went haywire and started expanding out of control. It has been expanding ever since then carrying the normal space it underlays with it. This is what is causing the dark energy phenomenon observed in the normal universe. The dark energy network is a realm where the laws of nature do not apply and one that responds directly to thought. It is such an alien place that even looking at it causes adverse effects on the minds of beings from the normal universe. It is a chaotic, mysterious, ever shifting fractal realm full of some seriously weird shit.
Lastly, there are recursions. These are created by the interaction between the dark energy network and the thoughts, dreams and stories of being living in prime worlds. Most are created by what is called fiction leakage. The rules of reality there conform to the rules of the story or myth they are drawn from. Once the recursion is created, the laws are set though. They do not vary according to what people believe. It is also possible to create custom recursions with whatever rules you want but this is a difficult process and there is no guarantee it will go as planned.