I think it really comes down to the ability to harness the fundamental forces behind electromagnetism. Up until this point the dyson swarm/sphere theories were built on the Idea that a star is the most optimal and long lasting fusion reactor and thus harnessing the 'top tier' energy source of the universe would be the be all end all.

However I do think a species that is able to master and modify completely the fundamental forces behind what holds our spatial dimensions together, we will realize there is more energy around us than we can manage to use. Everything up until that point will be ways to harness said energy in rudimentary ways of converting this energy into heat.

This is just a random internet persons thoughts. Would love to further my knowledge