@numericcitizen oh, no, that’s true, but it has what they call Actions which is basically what you end up choosing to do with the text you write. In the Action Directory on Drafts’s website, there are a couple of actions you can install: Post to Micro.blog and Post to Micro.blog (with title).
All you end up doing is writing your post (regardless of length), and when you’re ready, you choose the action to post to M.B. 😀
Drafts has full Markdown support, as well.