In an expanding universe, cosmic time is the same as atom time at rest with a constant expansion, but atom time does depend on relative velocity and acceleration. The red shifts of galaxy spectra are then due to increasing galaxy velocities with look-back time in the expanding universe. Blackhole singularity horizons, though, do stop atom time and yet still exist in the flow of cosmic time expansion.
In a collapsing universe, cosmic time is different from an atom time since atom time is never at rest given the variation of collapse rate. The red shifts of galaxy look-back spectra in the collapsing universe are then due to both galaxy cosmic age as well as the velocity of universe collapse. Blackhole horizons are no longer singularities even though they still stop atom time and still exist in the flow of cosmic time of collapse.
The fine-structure constant is one of the many constants that vary with universe collapse, but the fine-structure splittings of distant galaxies remain proportional to contemporary splittings. Many argue against universe collapse since the fine-structure splittings of distant galaxies are proportional to contemporary fine-structure splittings. However, the fine-structure splittings are proportional to ratio of transition energy and relativistic electron energy, En/(mec2), and this ratio is constant in the collapsing universe [see Griffiths and Schroeter, Introduction to QM, 2018, 7.3.2]. This is because while En and c both increase in the collapsing universe, me decreases over cosmic time.
The collapsing universe maintains the equivalence of mass and energy and therefore Lorentz invariance just as does the expanding universe. But the speed of light in the collapsing universe reflects the universe collapse rate only for each epoch, not for all epochs as in the expanding universe. The classical electron spin rate, c/α, in the collapsing universe is constant and so α varies in the same way as does c.
