The Archive App on Mac OSX has a submenu menu command that allows the current note to opened in an external editor then when you save in external editor that note is updated in the Archive app.
This work s in BBEdit but does not work for Drafts in Mac OSX.
When apps spawn off to other editors, they usually load a temporary file and round trip against that. Drafts isn’t file focused. It works primarily with its own database of notes. In that respect, it is more akin to say Evernote. Drafts can edit text, but it is not a traditional text editor like say BBEdit.
If The Archive app had a share extension would that over come any constraints from getting the edited text in Drafts back to The Archive?
That or even the clipboard would let you go back and forth, just not in the way you were initially asking about.
If there was a way to bridge the note file base with the note database it would be great so that changes in one would be reflected in the other.