Syntax Highlighting
"I am sorry, but everyone is getting syntax highlighting wrong" is the first proposed change to syntax highlighting I’ve found compelling. I never took to rainbow braces because I felt it made colors too busy, and distracted more than helped me. I definitely recommend reading this article by Nikita Propokov and thinking on it a bit.
I might take the linked VS Code theme for a spin, even though I’ve largely moved off the editor in favor of Zed (and to a lesser extent Neovim).