When a coworker pastes a screenshot of their syntax highlighted code with a black background into chat it is functionally 50% blank as my 55 year old eyes are not good at low contrast. Regular blue, purples and reds are often unreadable against a black background.
Fortunately syntax highlighting isn’t part of the code, it’s just how it’s displayed. There comes a point where pasting images of code, to preserve syntax highlighting, into chats, email, and documentation it’s not only a waste of space, it becomes an ADA issue. Use whatever fonts and themes in your editor, but keep those to yourself.