FOSS Markdown editor with live editor and proper folder structure?

Hi all, I would like to find a (local) Markdown editor that has both a live editor and can also open folders of MD files like a code editor. Currently, I am using Markor, which is awesome and works just like your normal code editor, but there is no live editing.

I would prefer if the app was customisable too, like how Markor lets you change the toolbar items. Additional functionality like Markor's to-do list feature is not necessary.

Obsidian is pretty neat but is not FOSS and creates "vaults" for your notes, making them less portable (I'd rather have something that can just opens any folder of MD files)

Joplin is a really nice program too with live editing, but again, it doesn't really work like Markor where you can open any sort of folder