Surely this can't be that universal, right? I will have to do this test at some point. I have astigmatism but I find the default bright version of websites frequently painful to look at. I have no clue why but I need the dark versions.
My strategy has been to use light mode all around but I have f.lux set to about 20% strength all day long. I also have my monitors dimmed a fair amount unless I want to display HDR. It also helps to have a bias light behind your screens if you can.
My goal was to get rid of the 2pm eye twitch and I've mostly got it.
If websites are generally too bright, you can save energy as part of increasing comfort by configuring your display to put out fewer nits (reduce its brightness setting). Usually people have the opposite problem, especially if there's direct sunlight on or near the screen, so that's probably what the factory default optimises for
