I use vanilla* VS Code with the built-in Markdown previewer. My notes are a flat structure of Markdown files (personal) or a single folder for each project (work).

*I have a plugin called Markdown Paste[0] to use a keystroke combo to save an image from the clipboard into a designated subfolder and insert the corresponding Markdown underneath my cursor. But it's nothing that can't be done by manually saving an image into a folder and typing the corresponding Markdown by hand

[0]: https://marketplace.visualstudio.com/items?itemName=telesoho...