In case anyone is interested. There is the Discord Enhancement Project which allows for custom CSS, themes, plugins.
Playing around I made this Homeworld theme quickly, before bed. Anyone interested, I can post the CSS code to be saved in notepad as .theme.
Otherwise there is this website which provides an easy WYSIWYG css builder for discord.
Home - Theme Editor (bdeditor.dev)

Other thoughts, naturally, would be an AOD theme...