Well, I guess it's put up, or shut up.

My prediction is the Webb will disprove Big Bang Theory;

https://medium.com/predict/the-webb-is-cast-72f2b8ab067d

The essential issue raised here, is that using the premise of "spacetime" to explain cosmic redshift ignores the central point about the speed of light always being measured as a constant. If relativistic space were expanding, wouldn't the speed of light have to increase proportionally?

Two metrics are being derived from the same light, one based on the speed and one based on the spectrum. Since the speed is still being used as the denominator, because if the spectrum were considered the denominator, it would be a "tired light" theory, the basic, mathematical logic doesn't stand up.

As for all the dark stuff, what if your accountant just wrote in a figure and called it "dark money," whenever he found a gap in the books? It used to be that when observation didn't match prediction, the theory was potentially falsified, but not with cosmology.

Inflation was a patch to explain aspects of a spatially flat, infinite, eternal universe within the frame work of BBT.

Epicycles were brilliant math, as description of our view of the cosmos, but the crystalline spheres were lousy physics, as explanation.

Math is modeling, it's not platonic. The purpose is to sort signal from the noise, not necessarily explain the noise.