

Literally in the first paragraph of the link you supplied:
“Comoving distance factors out the expansion of the universe, giving a distance that does not change in time except due to local factors, such as the motion of a galaxy within a cluster.”
It factors out the thing you are trying to use to create energy.




You can’t just use one way of measuring distance for one thing and another way for something else and then jam then together to get perpetual energy.