I wish that it was possible to use the Obsidian MD editor on MD notes external to a vault. That could be through stand alone “Obsidian Lite” app, or via an Obsidian VS Code plugin.
The need for this is that I have too many notes for them to fit into one, or even four vaults (without performance grinding to a halt), so invariably I also have lots of MD notes (not necessarily PKM notes, but just general stuff) living in my macOS file system (outside of the vaults) that I need to view/edit now and again. At present I use VS Code to do this to avoid having to introduce another MD editor (like Typora) into my workflow, but it’s jarring moving between the two editors.
Of course, this is a workaround until I can just shove all my 40K notes into one Obsidian vault and it work with the lightening speed that I currently enjoy with Obsidian.