Edit:
FOUND THE OPTION
So someone please delete this post!
Although the “night” mode in the appearance settings is almost good enough for most of the sites. It is not anywhere near to be perfect. There are many sites out there that gets broken with this mode turned on while the majority of sites works fine. So if an option can be implemented like Bromite or Kiwi Browser for Android which lets you toggle the dark mode on and off for individual websites. Please look into these open source browser codebase to see how they’ve implemented it and bring it to the brave. It is the one major feature that is keeping to jump in the brave boat for permanently.
Sorry about my broken English. And thanks in advance.
Two pictures of bromite browser (before and after)
GitHub source for code viewing: https://github.com/bromite/bromite