Good set of links eightning, thanks!
@franksisco Apologies, yes of course you know how to switch viewing modes. I now realize we’ve talked about CSS before. 
I think what you’re looking for is indeed the first link I posted using either the snippet or Oliver’s theme. Or maybe one of the plugins eightning linked could work?
I’ve updated the snippet to remove bold/italic decoration, remove the color from links, and remove the color from code blocks.
https://forum.obsidian.md/t/plugin-theme-for-plain-editing-view-source-mode-text/62435/2