"... Are units the difference between maths and reality? ..."

v. 5 n. 17

"Just why do things have units? Time, length, energy, mass. What are they? Are units the difference between maths and reality? Does that make any sense? If you find out, let me know." -- Sabine Hossenfelder, 5 Biggest Physics Mysteries #science #physics (youtube.com)

As to a description of "things" from the problem statement above:

"Given the entire scale of the Universe, from the subatomic to the tens of billions of light years of "known" space, one would think that some convoluted equation would be required to relate size to mass [mass-energy]. But all that seems to be needed is,

m ∝ r^2,

the mass of a "thing" is directly proportional to the square of the size of that thing. But what is that "thing"? "... As the mass of the Universe is proportional to its size squared, dark mass-energy is proportional to its size squared." *

Time. In terms of the above mass, length and energy, the Universe could be accelerating at

A ~ 10^-14 m/s^2. **

This change in motion of the Universe (inertia) has been associated with gravity, *** from which quanta were derived. ****

* Universal relationship between mass and size | LinkedIn

** Importance of a value for acceleration of the Universe | LinkedIn

***(4) An explanation of dark matter and dark energy from unmodified Newtonian gravity* | LinkedIn

**** Gravitational basis of quanta? | LinkedIn

Image: https://mannokbuild.com/precast/stairs-and-landings/