If you can build a Dyson sphere, you can probably modify a star; reduce and sequester its mass, for instance, so that you can use its energy more efficiently ov

If you can build a Dyson sphere, you can probably modify a star; reduce and sequester its mass, for instance, so that you can use its energy more efficiently over a longer term. And a star isn't necessarily the most efficient way to burn matter (think "heating your home with a forest fire" when you could have a nice well-designed furnace instead).