I can't be the only one who believes this...writing in a 2 panel markdown+preview side-by-side view is just horrible and backwards.
And I like the idea of markdown! Of course I want the ability to export to markdown for portability to the web. But for the love of god, don't make me surround my words in 4 character markup to make them bold, and then show me a second panel next to it so I can "preview" what bold looks like. Didn't we already solve this with 1980s word processors?
Hell, why don't we create a 3 panel writing view? On the left you can write in binary, in the middle you can see live base64, and on the right you can preview what it will look like to actual humans. Awesome!
The only good implementation of writing in markdown I've seen is Typora or Bear, which abstracts/fades away the markup after you type in a single view.
Notion also solves this by only allowing you to select from semantic HTML styles (ie. H1, H2, H3, etc) but you see what the final text will look like in one view. When you export, generating markdown is trivial since you're already using a markdown-esque set of options to style your text.