...any tip on getting that working faster? (it takes seconds!!!) I generally prefer to edit the plantuml markup and see the diagram update instantly (like ~<200ms) on the other half split. This is the workflow I have with VSCode + Markdown Preview Enhanced.
I prefer org mode deeper structure instead of markdown, but this kinds of usability stuff (there's also horrible latex formulas rendering, a thousand small papercuts that are fixable but nobody has time for that). From a practical perspective nothing just works out-of-the box the way I want on Emacs, and I'm just to lazy to properly customize everything...