One issue of ring worlds is traction (and Dyson spheres are much more complicated than that). Nothing we can imagine and certainly nothing we can build can take it but what if instead of rotating it above orbital speed to create gravity inside the ring we rotate it below orbital speed, create gravity on the outer surface and rely on materials that can withstand the compression?

Sunlight could still be reflected by a fleet of orbiting mirrors that wouldn't orbit the star in sync with the ring and thus would not be subjected to the structural forces of the ring. In case the ring is built around a smaller star with a spectral emission very different from the one preferred by the ring builders, the mirrors could adjust that too.