Why is that we use the speed of light to measure intergalactic distances, if space is expanding?

Wouldn't the speed of light have to increase, in order to remain Constant, to this expanding space? Spacetime is predicated on Special Relativity, remember?

Yet that would negate using it to explain redshift.

It seems like two metrics of space are derived from the same intergalactic light. One based on its speed, which remains relatively stable and one based on its spectrum, which expands.

In relating them, the speed is still assumed to be the denominator, or it would be a "tired light" theory.

I suspect that sometime in the distant future, when some generation of theorists refuse to spend their careers chasing the post empirical theorizing of previous generations, then much of what we are being told will be dumped.

Inflation, dark matter, dark energy, multiverses. Whatever it takes.