Here is a new report out on early dark energy, very interesting reading.
'Early dark energy' could explain the crisis in cosmology, https://phys.org/news/2022-12-early-dark-energy-crisis-cosmology.html
ref - The Hubble Tension and Early Dark Energy, https://arxiv.org/abs/2211.04492
My note. Cosmology calculators like https://lambda.gsfc.nasa.gov/toolbox/calculators.html
, show radius of the universe < 40E+6 light-years when CMBR light appears using H0=73 km/s/Mpc and z=1100 for the CMBR redshift. The reference paper link at arxiv.org has a 34-page PDF report too. I note some interesting issues here from the paper.
“3. EARLY-UNIVERSE MEASURES 3.1. The sound horizon, the cosmic microwave background, and large-scale Structure 3.1.1. The early Universe. The density of the early Universe (“early" here means within the first ~ 400,000 years of the Universe, before the CMB photons last scattered) was the same to <~ 10^-5 everywhere. It consisted of photons, baryons (~ 75% protons by weight, ~ 25% alpha particles, and electrons), all three neutrino mass eigenstates, and dark matter. The cosmological constant (or other form of dark energy) was dynamically insignificant…”
My note. Various cosmological assumptions are made. The cosmological constant pops out just right so the expanding universe is not destroyed within the first 400,000 years after BB. Extrapolating back from 400,000 years for the age of the universe back to Planck time and Planck length, could be interesting to read and show how nature created our universe, all by itself. Nature seems to get everything correct here in the early universe avoiding our destruction
Another note. Using cosmology calculators where H0 = 73 km/s/Mpc and z=1100 for CMBR redshift, the universe radius near 400,000 years is just < 40E+6 light-years. The diameter of the universe in BB cosmology, close to 80 million light years near 380,000 to 400,000 years old. Today, it is at least 93 billion light years across where CMBR redshift z=1100. No matter what is done it seems, 4D space is always expanding faster than c velocity. When the universe age is 400,000 years old, and the present, somewhere way out there using comoving radial distances calculated many billions of light years from Earth. 4D space is expanding faster than c velocity. Here is another interesting item in the 34-page PDF paper. "4.2. Early dark energy The basic idea behind early dark energy (EDE) is to postulate some exotic fluid that contributes ~ 10% of the total energy density of the Universe briefly before recombination and then has an energy density that decays faster than radiation at late time, so that it leaves the late evolution of the Universe unchanged."
My note, this looks like another fine-tuning problem in nature to accomplish this in BB cosmology.