Dark theme has been working great for me on opera, making all of the blinding light somewhat more manageable, however dark theme in my opinion should not be enabled on the discord side menu, because, as what I have experienced, all it does is make certain profile pictures un recognizable, and in some cases such as for my pfp, it just makes it pure white for some reason. Honestly dark theme shouldn't work on discord anyway because it already has its own form of dark theme.