So special relativity, which is a theory that comes out of thought experiments and pure mathematics, is "just a chemical reaction". How do you explain that an observer outside of a moving frame of reference will also see things differently?

Also, can you explain what you think "physical reactions" are? What causes them? Why would they happen at different speeds if time doesn't exist?

Can you explain which of the two statements you disagree with and provide an explanation:

1. The speed of light is constant in all frames of reference.

2. The laws of Physics apply in all inertial frames of reference.

If you disagree with neither of these statements, then the entirety of special relativity must follow from your logic. Which means you have to explain why these physical effects happen without being able to explain it through time dilation and other effects.