The standard model of cosmology presents a rather dismal picture of the future of the universe with dark energy and accelerated expansion leading to a cold death with no stars. The results of the JWST will be able to show the spectrum of light from the distant galaxies and cosmologists confidently predict that there will only be hydrogen and helium. When the results show that these galaxies are much older than the universe we will have to look for a new model of the evolution of the universe.
The key to understanding the evolution of the universe is to recognise that it is finite with a space boundary. When we think we are looking back to the beginning of time we are really looking out towards the observation horizon. The first galaxy formed around 126 billion years ago and the number of galaxies increases by a factor of 20 every 14 billion years.
In this model of the evolution of the universe the Cosmic Microwave Background is coming from radiating matter held at the event horizon of the universe. This has the effect of ensuring that all the matter formed within the event horizon stays within the event horizon. The expansion rate of the universe is constant. Renewal comes from galaxy mergers and dark matter provides neutrons for star formation.
This is a much more optimistic view of the future of the universe which can continue in a stable state for the indefinite future.
https://youtu.be/muCa08hlIDc
Richard