The expanding universe never added up.

If space actually expanded relativistically, the speed of light would have to increase, in order to remain constant.

Two metrics are being derived from the same light. One based on the speed and one based on the spectrum. So which is measuring the real space?

If the speed were the numerator, it would be a "tired light" theory, but as an "expanding space" theory, the speed of light is still the explicit denominator. The ruler against which this expansion is measured.

As Einstein said, "Space is what you measure with a ruler."

All the focus on the details and they miss the basics.