I use both auto (when available) and manual brightness adjustments, and the environment in which I do most of my computing gets ample natural light.
The problem persists, however, because as the linked posts notes light mode is far brighter than it used to be, and now if I crank brightness down low enough to feel comfortable I'm sacrificing contrast and color vividness to such a degree that (for me) it's actively distracting. So, dark mode on high brightness it is.
For code editing, I've always tended towards dark themes ever since they became readily available in IDEs in the late 2000s simply because syntax coloration "pops" so much more strongly than is possible with a light theme. When I use a light theme for code editing it feels almost like staring at a sheet of undifferentiated text in comparison.
Seconding this, light themes cripple syntax highlighting, which in turn makes it far more annoying to quickly scan through code and glean structure. You can make up for this to some degree with text decorations, but, well, with dark schemes you have that too.
> because syntax coloration "pops" so much more strongly than is possible with a light theme.
That’s why I mentioned alabaster: the only thing it highlights is comments and constants.
Nowadays I can’t stand “normal” themes even for a minute: they are like blinking Christmas lights for me, too much distraction.
Imaging reading the book where each word has different colors for nouns, verbs, what have you — nuts! :-)