To really appreciate energy, I think we need to reevaluate time.
As these mobile organisms, this sentient interface between our body and its environment operates as a sequence of perceptions, in order to navigate. So our experience of time is as the point of the present, moving past to future. Physics codifies it as measures of duration.
The reality is that change turns future to past. Tomorrow becomes yesterday, because the earth turns. Duration is the present, as the events coalesce and dissolve.
There is no literal dimension of time, because the past is consumed by the present, to inform and drive it. Causality and conservation of energy. Cause becomes effect.
Energy is "conserved," because it is this presence, creating time, temperature, pressure, color and sound. Time is frequency, events are amplitude.
So the energy goes past to future, because the events generated go future to past. Energy drives the wave, while the fluctuations rise and fall. No tiny strings necessary.
Consciousness also goes past to future, while the perceptions, emotions and thoughts giving it form and structure go future to past. Though it is the digestive, respiratory and circulatory systems processing the energy and feeding the flame, while the central nervous system sorts the information. Signals from the noise. Thus the tendency to think in terms of known and unknown, order and chaos, rather than energy and form. The patterns over the processes generating them. Maps over the territory.
Galaxies are energy radiating out, as structure coalesces in.
Our current cosmology has some enormous fudge factors, such as Dark Matter and Dark Energy.
The geometric model of spacetime says space either expands or contracts. Yet the expansion/outward curvature, is based on measurements of energy, while the contraction/inward curvature, is based on measurements of structure.
So consider the possibilities if energy and the information it expresses are not synonymous, given they go opposite directions of time.
Obviously the entropic tendency of energy is to radiate out, but why does structure coalesce in? Possibly because it's most basic pattern/expression is waves and the path of least resistance for waves is to synchronize, which is centripetal. Consider lasers are synchronized light waves. More energy in least form. Basically entropy for the energy is to radiate out, while entropy for the waves is to coalesce in. Black holes and black body radiation. Nodes and networks. Organisms and ecosystems. Particles and fields.
So if this dense, reasonably stable state we refer to as "mass" is simply a complex, intermediate stage between the barest bending of the light and the vortices at the center of galaxies, the reason there isn't sufficient matter to explain all the gravitational effect, is because we are looking at it backwards. Gravity isn't a property of matter, matter is an effect of this centripetal dynamic, which we refer to as gravity, as it pertains to the intermediate stage most appealing to our tactile environment. We put matter at the center of our physical models, like we once put the earth at the center of our cosmological models.
As for Dark Energy, if redshift is an optical effect compounding on itself, that would explain the parabolic curve in its rate.
One way light does redshift over distance, is as multi spectrum "packets," as the higher frequencies dissipate faster. Yet that would mean we are sampling a wave front, not observing individual photons traveling billions of lightyears. Thus a "loading" theory of light, where its quantification is a function of the material measuring devices. Getting back to energy and information as not being synonymous.
