I also wanted to create an export from Drafts to an Obsidian Inbox note. My solution was simple. The Drafts files are saved as .txt by default (if there’s a way to change that to .md, please let me know), but I simply use the Option + Command + S shortcut on a note and then I have a prompt for naming the file, which is already selected to save in the Drafts folder inside my vault. It’s automatically visible in my vault. However, in order to change the .txt to the .md file extension, I used the txt-as-md-obsidian plugin.
From this point on, I think the only thing that’s left is to just manually move the draft or do what I want to do with it in the vault. I don’t see a place to further automate or improve this; it’s quite simple.