Additionally noting that some of the dconf keys in the article have already been depreciated in the meantime. e.g. `/org/gnome/desktop/interface/gtk-theme` is to be replaced with `/org/gnome/desktop/interface/color-scheme`
(though even worse, some apps specifically look for the former, so you need to set the latter through the settings app, then the former through dconf anyways, for full dark theme through all apps!)
Partially, the other reason as far as I can tell is that the method of dark/light detection was based on the theme chosen, so if you wanted to mix light and dark themes (e.g. dark terminal, light otherwise), the app had to guess which theme to load. Instead now I think its a singular theme with subsections (and additionally, a 3 state theme selection, default, prefer-light, and prefer-dark. default suggesting that apps choose what is best for them).
For tens of years now, theming has been a prohibitively difficult thing to get into regardless: I'd rather try making a cohesive theme for windows than try with GTK.
For Windows theming, the Microsoft acknowledged WindowBlinds 11 and Curtains are both working options.
I haven't used it for a few years, but custom themes and styles is one of the key features for a customisable desktop environment and was half the fun from using something like Gnome or KDE now that Windows makes it hard and macOS makes it impossible.
Googling shows that as recently as 2022 there are articles on using themes. Is this a very recent change?
(though even worse, some apps specifically look for the former, so you need to set the latter through the settings app, then the former through dconf anyways, for full dark theme through all apps!)