Description of the issue:
I’d like to surf the web while having all pages turned dark. In Chrome this is achieved through a simple flag. Is there any way to have the same thing on Brave?
Yes, it’s the same flag: brave://flags/#enable-force-dark
YMMV, but IMHO the Dark Reader extension generally does a better job of it though, although at the expense of extension permissions and performance on complex pages. But this option is there if you want it.