Dark mode is a placebo. If your eyes hurt from the screen, then increase ambient light in the room so the amount of light around you is balanced and your irises will stay in same settings - main source of your pain.

If light would be a big problem, you would be going blind during sunny summer day.

Dark mode is fashion. If it were about headaches from bright screens, you would turn down the brightness.

And yet the site is in light mode?