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Expansion of the universe doesn't require energy. Overtime energy will probably become more and more dispersed(I am not qualified to answer this btw)

Because the amount is not the same. Energy is not conserved in general relativity, for multiple reasons. The first reason help to answer your question : Einstein equation with a cosmological constant say roughly : Energy = gravity + expansion. So expansion is caused by a specific form of energy, named dark energy, which is not conserved but increase with the universe's volume. The second reason for energy non-conservation, unrelated to your question, is because expansion modify the wave length of electromagnetic radiation (redshift), which mean photons loose energy.

Why is astrophysics always such a brain fuck

Science is why we can't have nice things. Place your faith in the great sky-waifu instead.