For more details on the transients being plate flaws, see Hambly & Blair.

"...the putative transients are likely to be spurious artefacts of the photographic emulsion. We suggest a possible cause of the appearance of these images as resulting from the copying..."

academic.oup.com/rasti/articl...

Updated plot — now with <<Peeples>> Time 😅

The data to rule out the hypothesis already exists. Sadly the authors made no attempt to test their assumptions against the real world.

Most of the Labbé candidates have been established to be AGN (LRDs). Furthermore Labbé et al. overestimated their redshifts systematically.

The Labbé et al. candidates were problematic, in that the stellar masses assume all the light came from stars. Since then a population of Little Red Dots has been discovered, which show evidence of being powered by AGN. Which would bias the masses high.

Monolithic collapse is not LCDM hierarchical structure formation. Under LCDM these galaxies would form much later.

These galaxies should also be detectable with JWST, but are nothing like anything identified so far.

There are lots of ways to rule this out. As is said in the paper there would only be 6 of these per Planck resolution element. So higher resolution telescopes like SPT and ALMA would resolve out this portion of the background into individual sources.

Today there are exactly zero z>15 spectroscopically confirmed galaxies. The highest redshift confirmed galaxy (MoMz14) has a tiny mass, around 10^8.1. Compare that to the proposal in the paper, where z>15 galaxies with masses of 10^11.5 and above should be common.

Also note that these galaxies are all actively forming stars, whereas the paper requires these galaxies become totally quiescent at this epoch. These candidates are not the proposed population.

Castellano et al., 2022 doesn't measure stellar masses. Donnan et al., 2023 only estimated one, for the galaxy that turned out to be misidentified. So no, these paper do not confirm such massive galaxies at all.

Donnan et al., 2023; Castellano et al., 2022 do not confirm galaxies with masses above 10^10.5 above z=10. Firstly these were only candidates, without confirming spectra. The most extreme object in Donnan et al. was confirmed to be a low redshift interloper.

In this paper the most massive galaxies form first, which is the opposite of the hierarchical galaxy formation in LCDM.

It does not use LCDM. The paper is based on Eappen et al. (2022), titled "The formation of early-type galaxies through monolithic collapse of gas clouds in Milgromian gravity". Milgromian gravity is MOND.

Then when you consider the effect this would have on CMB data, you can rule it out further:

So according to JWST these galaxies formed much later than this calculation assumes. The number of these early quiescent galaxies is also lower than the present day, showing some form at even later times. The paper is filled with random assumptions which are never justified.

It also disagrees with JWST observations. You say JWST has showed elliptical galaxies formed by redshift 15. The authors assume this to be the case, but offer no evidence. The most extreme known galaxy (Glazebrook et al.) formed at z=11. But the vast majority form much later (Nanayakkara et al.).

There are lots of problems with the claim. Firstly they are not assuming even LCDM, galaxies don't assemble that quickly in standard cosmology. What they are actually assuming is some MOND-inspired model. The calculation poses no challenge to LCDM, as it assumes a completely different cosmology.