It's worse than the original because the contrast is lower.
A lesson on why CSS should be able to specify the nits and colorspace you’d like your content to be displayed in, so it can be readable on your shitty screen, and avoid giving me headaches on my screen.
Also, the color calibration AFAIK does not specify brightness. Perhaps the headaches are not from contrast, but from too much brightness?
Text becomes painful if the contrast is too high, but if you have a cheap screen at 70 nits it won't ever be an issue.