I built a colorscheme for Vim [0] that is close to monochrome when I was worried about blue light (I've since had kids and now this kind of worry doesn't rate at all), and I basically use bold and highlights (I hate underlining, italics, and squiggles, but I think you can do all that too in the GUI version). I found it surprisingly usable.
I want to try some monochrome UI, but that amber is definitely not my taste. Let me see if there is a "paper-like" theme, or maybe I can make one myself.
[0]: https://github.com/camgunz/amber