I humbly refer to HC as a ‘model’ out of deference to the principle that ‘cosmologists are seldom right but never in doubt’ (Ladau).

Over the course of taking a detailed interest in the subject for 25 years I've seen the Hubble time change wildly. The value recently seemed to stabilise around 13.8 bnyr after making complicated adjustments for the Perlmutter observation that distance from apparent magnitude seemingly contradicts Hubble's law that redshift rises in direct proportion to distance. But now cosmology has another crisis; The Hubble Tension

https://arxiv.org/abs/2010.12164
The age of stars remains a matter of debate. Methuselah star

https://www.space.com/how-can-a-star...-universe.html
https://en.wikipedia.org/wiki/Stella...the%20universe.

How can we possibly tell the age of stellar remnants such as white dwarfs, black dwarfs, and black holes?

Plus things like this throw doubt on the whole galactic evolution idea

https://phys.org/news/2021-02-portra...formation.html
I think that if you look at that paper on gas halos you will see evidence for heavy element dust remnants in the halos.

Stellar evolution seems largely predicated upon no further gas in-fall. In quiet parts of galaxies that probably holds, but Andromeda is due to pass right through the Milky way in a few billion years time and such galactic collisions seem the long-term norm in the universe.

The Gödel metric applies to both the entire universe and to structures within it. According to this the Schwarzschild metric can apply similarly, depending on the observers frame of reference.

https://en.wikipedia.org/wiki/Schwarzschild_metric
"The Schwarzschild metric has a singularity for r = 0 which is an intrinsic curvature singularity. It also seems to have a singularity on the event horizon r = rs. Depending on the point of view, the metric is therefore defined only on the exterior region r > rs ,only on the interior region r < rs or their disjoint union."

Yes the universe must either contract or expand if only the simplest metric, the Schwarzschild metric, applies. However in the Gödel metric a rotation can stabilise it at constant size.

In the attached equations below I have shown an equality between those metrics. I have done this by effectively multiplying r both sides by pi, as pi r = L.

Any gravitationally closed space will have a radius r apparent from the outside but an antipode length L where L = pi r on the inside.

Regards, Pete.