It’s too dim and too low contrast for me when I dial it down and leaves afterimages when it’s enough. It is a personal thing.
Also, for programming I’m using not dark nor bright mode. Something like #ddd on #444 on well-calibrated settings. Almost all sites which implement dark mode are much closer to #neutron_star on #black_hole than that, so I hate them when they fail to follow an OS setting.
It's probably because you're using light dark text, on a dark background. To maximize eye-strain reduction:
* reduce monitor brightness
* increase contrast between background and text
For me, light grey background (no blaring, eye smashing white) with black text works well. The only point of "grey not white" is again, to reduce a smashed-in-the-face white background.
If one keeps the contrast difference low, that is, slightly-lighter dark text on dark background, then the monitor must be brighter to discern difference between text and background.
(Of course, as you have stated, this may not work for you.)
Also, for programming I’m using not dark nor bright mode. Something like #ddd on #444 on well-calibrated settings. Almost all sites which implement dark mode are much closer to #neutron_star on #black_hole than that, so I hate them when they fail to follow an OS setting.