Dyson spheres, Ringworlds, and Halos are all very impractical.
The first question is where the mass to build them comes from.
Second is where does the energy to build them come from and what is the *net* gain.
Third is that we now know that stellar output, light and particle winds, are not uniform in all directions nor constant. Certainly not our star and the evidence says it is an unusually "calm" one. A solid structure as fantasized would need a massively complicated reaction control system, consuming even more energy and, yes, mass.
Basically, any civilization with the resources and technology to build such beasts wouldn't actually *need* one.
A far more practical solution for a civilization that needed that much energy would be a constellation of solar power satellites relatively close to the star, far enough to avoid the direct impact of CMEs but close enough to capture a high irradiation.
And even that is speculative.
Fusion would be more likely to meet their needs and if we're to get speculative, figuring out how to break the strong nuclear force would be easier.
But in the end, the one question that line of speculation must answer is: what use requires that much energy consumption and how would they manage the environmental impact? Third Law of Thermo, for one.
The entire debate smacks of dancing angels on a pin.