The risks of blotting out your only livable planet’s biosphere is too great

If our Dyson sphere project has become large enough that this is a risk, then we’ve got ample energy to spare to artificially light Earth. Assuming we still want to keep it around at that point and not dismantle it for additional raw materials.

not to mention stuff like the dark forest theory.

Dark Forest only works in the context of a cheesy sci-fi story. Under real-world physics it fails utterly.